Application forms and confirmation documents often arrive as PDFs that still need a name, address, check mark, or handwritten signature. Printing, writing by hand, scanning, and converting back to PDF works, but direct PDF editing avoids the paper-and-scan round trip.
Browser Kitty PDF Fill & Sign can edit supported form fields already present in a PDF and can also place text, dates, marks, handwritten signatures, initials, and images over the page. The selected PDF is processed in the browser rather than uploaded to a Browser Kitty server.
There are two basic ways to enter text into a PDF
Some PDFs contain real form fields, so clicking a name or address box lets you type directly. PDF Fill & Sign supports common AcroForm fields including single-line and multiline text, checkboxes, radio buttons, dropdowns, and choice lists.
Other PDFs are effectively paper forms turned into pages: they may look like they contain boxes, but those boxes are not interactive. In that case, use the Text tool to place text over the desired location.
1. Open PDF Fill & Sign
Open PDF Fill & Sign from Browser Kitty. No installation or account is required.
The hosted version first downloads the application HTML. PDF parsing, rendering, form editing, signature creation, and final PDF generation then run in the browser.
2. Open the PDF you want to fill in
Choose one PDF. On desktop, you can also drag and drop it onto the start screen. After loading, the pages appear and multi-page documents can be navigated from thumbnails.
PDF Fill & Sign v1.0.0 handles one PDF at a time with a 100 MiB input limit. Password-protected PDFs are not supported in v1.0.0.
3. Fill the form fields already present in the PDF
When the PDF contains a supported form field, select it and type directly into the field. Typical examples are name, address, phone number, notes, checkboxes, and choice fields.
Use Tab / Shift + Tab or the on-screen previous/next controls to move between fields. Read-only fields and other unsupported fields remain non-editable.
- Tab: move to the next supported field
- Shift + Tab: move to the previous supported field
4. Add text where no form field exists
Use the Text tool for locations that do not contain form fields. Enter a name, address, note, or other content and position it where needed. The position, content, font size, and color can still be adjusted after placement.
Text and date additions are saved as PDF FreeText annotations rather than by rasterizing the entire page. The app does not embed a Browser Kitty-provided Japanese font file into those annotations, so reopen important documents in the PDF viewer you normally use and verify the final appearance.
5. Add dates and ✓ / × / ○ marks
Use the Date tool for application dates, confirmation dates, and similar entries. A normal Text item can also contain a date, but the dedicated tool makes date-only placement quicker.
For printed yes/no boxes that are not real PDF checkboxes, place ✓, ×, or ○ anywhere on the page. These marks are stored as vector Ink annotations where practical.
6. Create a handwritten signature or initials
Choose Signature and draw with a mouse, finger, or pen. On a phone, drawing directly on the screen can be easier than using a mouse. Place the result on the page, then adjust its position and size.
Initials can be created separately. Signatures and initials drawn inside PDF Fill & Sign are stored as vector Ink annotations rather than as screenshots of the drawing area.
7. Add a signature image, stamp, or other image
Existing signature images can be placed as PNG, JPEG, or WebP. A signature drawn in the app is an Ink annotation, while an imported signature is an image annotation.
Image / Stamp can also place stamps, company logos, photos, and other images. A transparent PNG often works better when a photographed stamp includes an unwanted white background.
8. Move and edit added content
Text, dates, marks, signatures, initials, and images added by Browser Kitty remain selectable after placement. Small positioning errors do not require restarting the document.
On desktop, arrow keys make small moves and Shift + arrow keys make larger moves.
9. Use Undo / Redo and zoom for corrections
PDF Fill & Sign supports Undo / Redo. When you are not actively typing inside a form field, use Ctrl / Cmd + Z for Undo and Ctrl / Cmd + Shift + Z or Ctrl / Cmd + Y for Redo. Supported form-value changes participate in the history.
For precise placement, use Ctrl / Cmd + wheel on desktop or two-finger pinch zoom on a phone. After zooming on mobile, pan the PDF with one finger.
10. Sign a PDF on a smartphone
On phones, persistent Tools / Pages / Selected / Save actions appear at the bottom. Draw the signature with a finger and place it directly on the PDF.
Signature and save dialogs scroll internally on small screens, so a phone can be convenient when the main task is simply to add a handwritten signature.
11. Decide whether to save the signature on the device
The selected PDF and current editing session are not normally persisted. Signatures and initials are stored in IndexedDB only when you explicitly enable Save on this device, and saved items can be deleted from the signature dialog.
On a shared family or workplace device, leave device storage disabled when you do not want the signature to remain available after the session.
12. Review the “Flatten entered values” option
Flatten entered values is enabled by default when saving. With it on, the current appearance of supported form values is written into the PDF and the original widgets are hidden from viewing and printing, which is useful for submission copies.
With it off, supported fields remain interactive where the source PDF and PDF.js save path allow it.
This strategy does not physically remove the underlying AcroForm field dictionaries; it writes the appearance and hides the original widgets.
13. Save the completed PDF and reopen it
Choose Save PDF after reviewing the document. The source PDF is not overwritten; the default output is a separate file with -filled.pdf appended to the source name.
For important submissions, close and reopen the saved PDF. Verify text, marks, dates, signatures, stamps, placement, Japanese rendering, and form behavior in the actual file you plan to send.
A handwritten visual signature is not a certificate-based digital signature
A signature added by PDF Fill & Sign is a visual signature: it places the appearance of a handwritten signature on the PDF. That is different from a certificate-based digital signature that uses cryptography to help verify signer identity and document changes.
Signing requirements vary by document and process. PDF Fill & Sign does not provide certificate signing, identity verification, signature requests, audit trails, or contract-management workflows. Follow the recipient's required method when one is specified.
A PDF signature field does not turn this into certificate signing
Some PDFs contain signature fields. PDF Fill & Sign can use such a field as a visual placement guide for a handwritten or image-based signature.
It does not cryptographically sign that field with a certificate.
Limits for XFA forms, required fields, and password-protected PDFs
v1.0.0 does not edit existing XFA form fields, though text, dates, marks, signatures, and images can still be placed over a page that can be displayed.
Required-field warnings are advisory and do not forcibly block export. Password-protected PDFs are not supported in v1.0.0.
Are the PDF and signature uploaded to a server?
PDF Fill & Sign processes the selected PDF, form values, handwritten signatures, initials, stamp images, and other edits inside the browser. The app does not upload the selected PDF to an external server for processing.
The generated HTML uses a Content Security Policy containing connect-src 'none', and PDF.js plus its Worker are embedded in the application.
The hosted version still needs the initial HTML request
Opening the hosted Browser Kitty or GitHub Pages version requires an initial request for the application HTML. After that, the selected PDF is not sent to Browser Kitty for processing.
For disconnected use, a generated standalone HTML can be saved and opened locally with file:// in a compatible browser.
How does this differ from other online PDF-signing services?
Services described as online PDF signing do not all handle files the same way. Some upload a document to a server for editing, while browser-local tools can work without sending the selected file to an application server.
For sensitive documents, check where the selected PDF is actually processed rather than relying only on the fact that the tool runs in a browser.
A practical fill-and-sign workflow
A simple way to avoid confusion is to separate existing-form editing from page overlays, then verify the exported file itself at the end.
Review every page and reopen the actual PDF you plan to submit.
Some procedures still require paper, ink, or a specified signing method
Being able to place a signature on a PDF does not mean every process accepts that method. Some procedures require an ink signature on paper, an original document, a specific seal, or a specified electronic-signature method.
Check the recipient requirements before choosing the signing workflow.
Step by step
- Open PDF Fill & Sign and choose one PDF.
- Fill supported AcroForm fields directly when they exist.
- Add Text, Date, ✓, ×, or ○ overlays where the PDF has no interactive field.
- Draw a Signature or Initials with a mouse, finger, or pen, or choose an existing signature image.
- Add a stamp or other image when needed and adjust its position and size.
- Review every page and use Undo / Redo or zoom for corrections.
- Before export, decide whether Flatten entered values should be on or off.
- Save the completed PDF as a separate file.
- Reopen the saved PDF in your normal viewer and verify text, signatures, Japanese rendering, and form behavior.
PDF Fill & Sign
Fill PDF form fields, add text, dates, marks, handwritten signatures, initials, or images, and save the completed PDF locally.
Tips and limitations
- For a submission copy, always reopen the saved PDF and inspect the real output file.
- On a shared device, leave Save on this device disabled for signatures and initials.
- A transparent PNG usually works better when placing a stamp without a white rectangular background.
- A visual handwritten signature is not the same as a certificate-based digital signature, so check recipient requirements.
- Required-field warnings do not block export, so verify missing fields yourself.
Frequently asked questions
Can I type text into a PDF?
Yes. Fill supported AcroForm fields directly, or place a Text item anywhere when the PDF has no interactive field.
Can I add a handwritten signature to a PDF?
Yes. Draw a signature with a mouse, finger, or pen and place it on the PDF. Initials are also supported.
Can I place a signature image on the PDF?
Yes. PNG, JPEG, and WebP signature or stamp images can be placed on the page.
Can I add check marks to a PDF?
Yes. Use existing supported checkboxes or place ✓, ×, and ○ marks anywhere on the page.
Can I sign a PDF on a smartphone?
Yes. Use two-finger pinch zoom, one-finger panning, and draw the signature directly with your finger.
Can I make filled form values harder to edit later?
Enable Flatten entered values to write the current supported form appearance and hide the original widgets from viewing and printing. This does not physically delete the underlying AcroForm dictionaries.
Is the handwritten signature a digital signature?
No. It is a visual signature, not a certificate-based digital signature that verifies identity or document integrity cryptographically.
Can I use it for contracts?
Only when the process accepts a visual signature. If certificate signing, identity verification, audit trails, or a specified e-signature service are required, use the method requested by the recipient.
Can it open password-protected PDFs?
Not in v1.0.0.
Can it edit XFA forms?
It does not edit existing XFA fields. If the page can be displayed, text, signatures, and other overlays can still be added over it.
Does it overwrite the original PDF?
No. The completed document is normally saved as a separate file with -filled.pdf added to the source name.
Are the PDF and signature sent to a server?
No. PDF parsing, form editing, signatures, image placement, and final PDF generation run in the browser. The hosted app needs the initial HTML request, but it does not upload the selected PDF to a Browser Kitty server.