# Fill in a PDF Form — Every Field, In Your Browser

> Read a PDF's interactive form fields, fill them in, and optionally lock the answers.

To fill in a PDF form, add the file and its interactive fields are read straight out of the document — text boxes, checkboxes, radio groups and dropdowns — each with the right control and any answers already in the file. Fill them in and download the completed form. Switch on "lock the answers" to flatten them into the page so nobody can change them, which is what you want before returning a signed application. Everything runs in your browser, so a tax return or a medical form is never uploaded.

**URL:** https://convertto.tech/t/fill-pdf
**Category:** PDF Tools (https://convertto.tech/c/pdf-tools)
**Privacy:** Runs entirely in the browser; no upload
**Cost:** Free, no sign-up
**Last updated:** 2026-08-01

## Key facts

- **Field types:** Text, multi-line text, checkbox, radio group, dropdown and list
- **Privacy:** Runs entirely in your browser — nothing is uploaded
- **Cost:** Free, unlimited, no sign-up

## How to use

1. Select your pdf form — the file stays on your device and is never uploaded.
2. Enter or paste your answers.
3. Turn "Lock the answers" on or off as needed.
4. Press Run, then download the result when it is ready.

## FAQ

### I filled the form but the saved file looks empty.

That is a viewer trusting a stale appearance stream — the value is in the file, but the cached picture of the field is not. This regenerates every field's appearance after writing, which is exactly the step most form fillers skip.

### My PDF shows no fields at all.

Then it is not an interactive form. A scanned or printed form is a flat page with lines drawn on it and has no fields to fill. Use Sign PDF to place text and a signature onto the page instead.

### Should I lock the answers?

Before sending a completed form back, yes — flattening turns the values into ordinary page content so they cannot be altered, accidentally or otherwise. Leave it off while you are still working, because flattening is not reversible.

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