Fill PDF Form

How to fill in a PDF form

1. Drop a PDF form on the drop zone, or click it to choose one. The tool reads its fields and shows how many can be filled.
2. Under Form fields, fill in the fields. They are grouped by page, in the order the form defines them. Hover a field to see its internal name; grey fields are read-only.
3. Made a mistake? Reset to original values puts back what the file contained.
4. Tick Flatten the form (answers can no longer be edited) if you’re sending a final version.
5. Click Save filled PDF, then Download. The file is named after the original, for example tax_form_filled.pdf.

Which forms work

This tool fills AcroForm fields, the standard interactive fields of the PDF format. That’s what you get from Adobe Acrobat, LibreOffice, Word’s PDF export with form controls, and most government and business forms. Every field type is supported:

• Text fields, single-line or multi-line, including fields with a maximum length (the tool tells you if an answer is too long);
• Check boxes;
• Radio buttons, shown as one group with a (none) choice to clear it;
• Drop-down lists, including editable ones where you can type your own answer;
• List boxes, with multiple selection when the form allows it.

The labels come from each field’s tooltip when the form has one, otherwise from its name. Signature fields and push buttons are listed but have nothing to fill; to add a handwritten-style signature, use a separate signing tool after filling.

Some forms don’t have fields at all: scanned paper forms, or PDFs where the boxes are just drawn lines. This tool can’t type on those.

XFA forms

A few forms, often from government agencies, are XFA forms, made with Adobe LiveCycle or AEM Designer. Their fields are described in an XML layer that only Adobe Reader understands. An XFA-only form has no regular fields, so the tool shows a message and can’t fill it: open it in Adobe Acrobat Reader instead. Many XFA forms also carry regular fields as a fallback. In that case the tool fills those and removes the XFA layer when saving, so every reader shows your answers.

Fonts and special characters

After filling, the tool redraws each changed field with pdf-lib in Helvetica, one of the standard PDF fonts. Helvetica covers English, French, Spanish, German and other Western European languages, plus common symbols like € and curly quotes. It can’t draw Cyrillic, Greek, Chinese, Arabic, emoji or letters like Polish ł.

When an answer contains such characters, the tool warns you. If you save without flattening, the value is stored and the file asks PDF readers to draw it with their own fonts: Acrobat, browsers and most desktop readers do this correctly. Flattening needs a drawn appearance, so it’s refused for those fields until you remove the characters.