Fill PDF Form Fields Online
Find and fill form fields in a PDF, then lock the values.
🔒 Your file is processed inside your browser. It is never uploaded or saved.
What is PDF Forms?
Many official PDFs contain interactive fields. This tool first lists the field names, then lets you provide values in a simple Name=Value list. You can keep the fields editable or flatten them so the answers become fixed.
How to fill PDF form fields
- Upload a fillable PDF and press Start with the values box empty to see the list of field names.
- Write one line per field, such as FullName=Ali Khan.
- Choose whether to keep fields editable or flatten them.
- Press Start again and download the filled PDF.
When PDF Forms is useful
Repeat paperwork
Fill the same form for several people.
Locking answers
Flatten a completed form before sending.
Inspecting forms
See what fields a PDF contains.
Tips for better results
Field names must match exactly, including capital letters. For checkboxes, use yes or no. If the PDF has no fillable fields, the tool tells you; in that case use Edit PDF to place text on the page.
Good to know before you start
Fillable PDFs identify each box by an internal name, which is often not the label you see on the page, for example "topmostSubform[0].Page1[0].f1_01[0]". That is why the tool lists field names first: copy the exact name into your list and add the value after an equals sign. Text fields accept any text, check boxes accept yes or no, and drop-downs accept one of their options. If you type a field that does not exist, the tool names the problem instead of silently skipping it. Choosing Flatten at the end makes the answers permanent, which is useful for forms you plan to submit.
Why use PDFToolkit
When you fill PDF form fields with PDFToolkit, the work stays on your own device. Your contracts, ID scans and invoices are processed in the browser and are never sent to a server.
- Private: no upload, nothing saved.
- Free: no sign-up, no daily limit and no watermark.
- Fast: no waiting for files to travel over the internet.
- Everywhere: Windows, Mac, Linux, Android and iPhone.
Frequently asked questions
How do I know the field names?
Run the tool with the values box empty and it lists them.
What does flatten do?
It turns fields into fixed page content that can no longer be changed.
What about checkboxes?
Use yes, true, 1, x or on to tick, anything else to untick.
Is the form uploaded?
No.