Fill PDF Form
Open a fillable PDF and every form field appears as a simple list grouped by page: text boxes, checkboxes, radio buttons, dropdowns and lists. Fill them in, flatten the form if you like, and download the completed PDF. Nothing is uploaded.
This PDF has no interactive (AcroForm) fields, so there is nothing to type into. It may be a scanned or "flat" form, or use the XFA format that only Adobe Reader can fill. You can still add text, a date or your signature on top of the page with the Sign PDF tool.
How to use the Fill PDF Form
- Open your PDF form by dropping it on the box or clicking to browse.
- Fill in the fields. They are listed page by page; use the search box to find a field in a long form.
- Check your answers: changed fields are marked with a green edge and the counter shows how many are filled.
- Tick Flatten if the recipient should not be able to change the answers (optional).
- Press Fill & download PDF to save the completed form as name-filled.pdf.
PDF form field types explained
| Field type | What it looks like in the PDF | How you fill it here |
|---|---|---|
| Text field | A box you type into; can be single-line, multi-line, limited to a number of characters or hidden like a password | Text input or larger text area; the maximum length is enforced |
| Checkbox | A small square that is ticked or empty | Tick or untick “Checked” |
| Radio buttons | A group of round buttons where only one can be on | Choose one of the listed options, or None |
| Dropdown (combo box) | A closed list that opens when clicked; some also accept typed text | A select menu, or a text box with suggestions for editable dropdowns |
| Option list | An open, scrollable list; may allow several choices | A list where you can select one or several entries |
| Button / signature | Push buttons that run scripts, or digital signature boxes | Not editable here; use Sign PDF to add a visible signature |
AcroForm, XFA and flat forms
Most fillable PDFs use AcroForm fields, the form system that is part of the PDF standard (ISO 32000). Every field has a name, a type, a value and one or more “widgets”, the visible boxes on the page. This tool reads those fields, writes your values into them and regenerates their appearance so the answers show up in every PDF viewer, including browsers and phones.
XFA forms are an older Adobe format where the form is described in XML inside the PDF. They are deprecated in PDF 2.0 and only Adobe Reader can display dynamic XFA forms. A flat form is just a picture or text of a form with no fields at all, for example a scanned paper form. Flat forms can't be “filled” as such, but you can place text, dates and signatures on them with a PDF annotation or signing tool.
Tips for filling forms correctly
- Dates: follow the format printed next to the field (for example MM/DD/YYYY); the form may check it when opened in Adobe Reader.
- Long answers: if text is cut off in a small single-line box, shorten it; PDF viewers do not enlarge a field to fit.
- Before you flatten, open the downloaded copy and check every page, because a flattened form cannot be edited.
- Read-only fields are shown greyed out; they are calculated or locked by the form author.
Frequently asked questions
How do I know if my PDF is fillable?
Open it here. If the PDF contains interactive AcroForm fields they are listed straight away. If you see the message that no fillable fields were found, the form is flat (for example a scan) and you can add text on top of it with the Sign PDF tool instead.
What does flattening a PDF form do?
Flattening turns the filled fields into ordinary page content. The answers look exactly the same but can no longer be edited, and the form fields disappear. Keep an unflattened copy if you may need to change something later.
Why does a field show a strange name?
The names come from whoever created the form. Programs like Adobe LiveCycle produce names such as form1[0].page1[0].name[0]; the tool shows a cleaned-up version and the original name underneath so you can match it to the page.
Why can't I type emoji or some special characters?
Filled-in values are drawn with the form's standard PDF font, which only covers Western Latin characters. Emoji and letters from other scripts cannot be encoded, so the tool asks you to remove them.
Does this work with XFA forms?
Pure XFA forms (dynamic forms made with Adobe LiveCycle) only work in Adobe Reader. Many XFA forms also contain normal AcroForm fields, which this tool fills, but some viewers may still show the XFA version.
Is my form uploaded anywhere?
No. The PDF is read and filled entirely in your browser using the pdf-lib library, so personal details you type never leave your device.