How to fill in a PDF form

Last updated: June 25, 2026

PDF forms come in two flavours, and the easiest way to fill each is different. The good news: in both cases you can do it for free, without buying or installing anything.

Case 1 — The PDF has interactive fields

If clicking on a blank box places a cursor and lets you type, it's an interactive (AcroForm) PDF. You don't need special software at all:

Open the PDF in your web browser (drag it onto a new tab in Chrome, Edge or Firefox).
Click each field and type your answers; tick checkboxes by clicking.
Use the browser's Save / Print → Save as PDF to keep a filled copy.

Case 2 — It's a flat PDF or a scan

If nothing happens when you click — it's a flat document (often a scan) with no real fields. Two reliable free routes:

Print, fill by hand, digitise again. Print it, fill it in, photograph or scan the pages, then rebuild a PDF with our JPG to PDF tool. (See our guide on scanning with your phone.)
Annotate on a tablet. Many tablet apps let you write on a PDF with a stylus and export it back.

After filling: tidy up

Need to combine the form with other documents? Use Merge PDF. Is the filled scan too big to email? Run it through Compress PDF.

A note on privacy

Forms often contain personal details — names, addresses, ID numbers. Filling an interactive form in your browser keeps it on your device, and all of robinpdf's tools process files locally without uploading them.

Frequently asked questions

How do I know if my PDF has fields?

Open it and click a blank box. If a text cursor appears, it's interactive; if nothing happens, it's flat.

Can I fill a form on my phone?

Yes — interactive PDFs can be filled in most mobile browsers, and the scan-and-rebuild route works from a phone too.