Fill in a PDF form on any device
Open a PDF and fibub looks for its form fields. If it finds any, they appear as an ordinary form: text boxes, tick boxes, drop-down lists and choices. Fill them in and download the PDF. If the PDF has no fields (a scanned form, or a document someone printed to PDF), use Type anywhere: tap the page to put text, a tick mark or a date exactly where you want it.
Everything happens in your browser. Your PDF, and what you type into it, are never uploaded, and the page keeps working with no internet once it is open. Nothing you type is saved after you close the page.
When the form needs your signature too, use sign PDF on the filled copy; to make a big filled-in file smaller for email, use the file compressor.
How to use it
- Choose your PDF, or drop it on the box.
- If form fields are found, fill them in under Form fields. Choose from the lists, tick the boxes.
- For anything else, type the words in Text (or use the Date text box), press Add text, Add date or Add tick mark, then tap the page. Drag the box to move it and pull the square corner to change the size. The x removes it.
- Press Download filled PDF. Open the file and check it before you send it.
What each setting does
- Flatten the form: turns the fields into plain page content. Use it when the form must not be changed again, or when a viewer shows the fields blank. Leave it off if you still want to edit the fields later.
- Add text / date / tick: marks that are drawn straight onto the page, not form fields.
- Arrow keys: nudge a selected mark (hold Shift for bigger steps).
Worked example
A tenancy form with Name, Address, a “Smoker” tick box and a “Term” drop-down: type your name and address, leave the box un-ticked, choose “12 months”, and download. Opening the file in any PDF viewer shows those values in the right places, and a form reader sees the same values you typed.
FAQs
Why are my typed values not shown on the page picture above? The picture shows the PDF as it was opened. Your values are written into the downloaded file.
Some fields are missing. Only the standard form field types are read: text, tick box, drop-down, list and radio choices. Signature fields are left alone; use sign PDF for those.
It says the PDF is locked. Password-protected PDFs cannot be changed. Remove the password in the program that made it, then try again.
Are my files stored? No. Everything happens on your device.
Where the numbers come from
- Form fields are read and written with pdf-lib (MIT); page pictures use pdf.js (Apache 2.0). Both run in your browser. No figures or rules.
Standard scientific values, such as constants, atomic weights and melting points, are facts found in every textbook; we name where ours were checked. If you are an author or publisher and want a value, a credit or a table changed or removed, tell us and we will act quickly.
Last updated 2026-11-10.