Fill in a PDF form
Open a fillable PDF and every field it has appears as a box you can type in, in the order it sits on the page. Fill it in, lock the answers if you like, and download.
Updated November 5, 2026 · 2 min read
Choose the PDF form to fill
Forms with fillable fields, like tax forms, applications and order forms.
Your file never leaves your device. The form is filled right here in your browser. Your answers aren't uploaded or saved anywhere.
On this page
How to fill a PDF form
- 1
Open the form
Choose the PDF. The tool finds its fields (text boxes, checkboxes, choices and lists) and groups them by page.
- 2
Fill it in
Type your answers. Labels come from the form itself, and required fields are marked with an asterisk.
- 3
Lock it or keep it editable
Tick Lock the answers (flatten) to make them part of the page. Leave it off if you or someone else will edit the form later.
- 4
Download
Tap Download filled PDF, and open it to check the answers before you send it.
When a PDF has no fields
Many PDFs only look like forms: the blanks are printed lines, not boxes you can type in. The tool tells you when that's the case. To type anywhere on a page, add a date or sign, use Sign a PDF free, where you place text, date and signature fields wherever you need them.
Tips for common forms
- Get the current version. Government forms such as the W-9 are fillable PDFs; download them from the agency's own site so the fields are there. See how to sign a W-9 online.
- Mind special characters. Standard form fonts cover English and Western European letters like é, ñ and ü. Others, such as Ł, are flagged so they don't print as question marks.
- Sign after filling. Signature fields aren't typed into here: fill the form, then sign the downloaded copy.
- Flatten the final copy you send, so nobody changes an answer by accident.
When someone else fills it in
If a client or employee is the one filling the form, send it to them instead. In SignMaster you add the fields once and save it as a template; each person fills it in and signs from a link, and their answers come back with the signed PDF.
Questions? Answers.
Why don't I see any fields?
Either the PDF has no fillable fields, or its form is an XFA form that only Adobe Reader understands. Use Sign a PDF free to type on the page instead.
Is my information uploaded?
No. Your answers stay in your browser and are written into the PDF on your device. Nothing is stored after you close the page.
What does flatten mean?
It turns each answer into ordinary page content and removes the form fields, so the answers can't be edited. Keep an unflattened copy if you may need to change something.
Can I fill a PDF on my iPhone?
Yes. Choose the PDF from Files, fill it in, and the finished copy saves to your downloads.