PDF guide
How to Fill In a PDF Form on Your Computer or Phone
Updated 27 September 2026 · 3 min read
Printing a form, filling it in by hand and scanning it back is the slowest way to do paperwork — and handwriting rarely scans well. Most PDF forms can be completed on screen in a few minutes. How you do it depends on one thing: whether the form has fillable fields, or is just a picture of a paper form.
Open the free Fill PDF FormFillable or not? A ten-second check
Open the form in Fill PDF Form. If it has fillable fields, you’ll see a list of them straight away — text boxes, tick boxes, choices. If it doesn’t, the tool tells you the PDF has no fillable fields. That usually means it was scanned from paper or exported without form fields, and you’ll use the method in the second half of this guide.
Filling in a form with fields
- Open Fill PDF Form and choose the PDF.
- Type into each text field, tick the boxes and choose options from any lists.
- Decide whether to lock the answers (see below).
- Select Save filled PDF and download it.
- Add a signature if the form needs one, with Sign PDF.
Should you lock the answers?
| Lock (flatten) the form when… | Leave it editable when… |
|---|---|
| You’re sending the final version to an organisation | Someone else still has to fill in their part |
| You don’t want answers changed after you send it | You may need to correct something later — keep an editable copy too |
| The recipient’s software shows form fields oddly | The organisation asks for a fillable form back |
Locking turns the fields into ordinary text on the page, so what you typed looks the same in every PDF viewer and can’t be edited by accident.
Filling in a scanned form (no fields)
For a form with no fields, use Edit PDF, which lets you place text anywhere on the page.
- Open the form in Edit PDF and choose the Text tool.
- Tap just above each line or inside each box and type your answer.
- Keep one font size throughout — usually 10 or 11 point matches printed forms well.
- For tick boxes, type a ✓ or an X inside the box, or draw a small box shape over it.
- Zoom in to line everything up, then download the completed form.
Getting the details right
- Dates: use the format the form asks for. Australia and the UK write day/month/year; the US writes month/day/year.
- Names: match your ID exactly, including middle names, if the form is official.
- Blank answers: write “N/A” rather than leaving a required box empty, unless the instructions say otherwise.
- Attachments: if the form asks for supporting documents, combine them into one upload with Merge PDF.
On a phone or tablet
Both tools work in mobile browsers. Filling a fillable form on a phone is comfortable; for a scanned form with lots of small boxes, a tablet or laptop is easier, because you’ll zoom in and out a lot.
Before you send it
- Open the saved PDF and check every page — especially that answers appear, not just blank fields.
- Sign and date where required with Sign PDF.
- Black out anything the recipient doesn’t need with Redact PDF.
- Check the file size against the upload limit; Compress PDF can help, especially for scanned forms.
Privacy
Forms tend to collect exactly the information you want to protect: dates of birth, addresses, account numbers. KitWren fills forms in your browser, so the completed document is never uploaded.