How it works
- Place markers in your document - In Word, LibreOffice, InDesign, or any editor that exports PDF, type placeholder markers exactly where you want form fields.
- Export to PDF - Save or export your document as a PDF file.
- Drop your PDF here - Drag it onto the Tool tab's drop zone, or tap to browse. Your file never leaves your device.
- Review detected fields - FormMyPDF analyses the PDF and shows all detected markers. Click Edit fields to open the visual editor, or Download to generate the fillable PDF immediately.
- Download the fillable PDF - Your browser generates the final PDF with all form fields applied.
Customising markers
The Markers tab lets you change the placeholder strings and detection settings for each field type. Click the edit button on any row to modify it inline - changes apply immediately. When you switch back to the Tool tab with a PDF already loaded, re-analysis runs automatically with the new settings. Fields you have moved or resized in the editor are preserved; unedited marker fields are replaced with fresh positions from the new analysis.
Visual field editor
The editor lets you fine-tune field positions before downloading:
- Move - drag any field to reposition it on the page.
- Resize - drag the edge handles. Text fields resize horizontally only; text areas resize in all directions. Checkboxes and radio buttons are fixed size.
- Add a field - click a tool in the toolbar (Checkbox, Radio, Text, Textarea), then click anywhere on a page to place it. Click the active tool again to deactivate it.
- Select - click a field to select it. Shift- or Ctrl-click to multi-select. Drag on an empty area to rubber-band select a region.
- Delete - press Delete or Backspace with fields selected, or click the × button on a single selected field.
- Align - with multiple fields selected, the alignment toolbar appears. Align left, centre, right, top, middle, or bottom edges, and distribute fields evenly.
- Undo / Redo - Ctrl+Z / Ctrl+Shift+Z (or ⌘Z / ⌘⇧Z on Mac).
- No markers found? - The editor opens automatically so you can add fields manually.
Supported source editors
Microsoft Word, LibreOffice Writer, Adobe InDesign, Google Docs (Download as PDF), Apple Pages - any app that exports a PDF with real selectable text.
Marker reference
Type these exactly in your source document. Click Edit to customise.
| Marker | Creates | |
|---|---|---|
[_] | Checkbox | |
[o] | Radio button - all [o] within ~30 pt vertically share one group | |
____ | Single-line text field (4+ underscores - width sized to run length) | |
[[ ]] | Multi-line text area - standalone or auto-detected table cell |
Tips
- Place
[_]and[o]before the label text. - Place underscore runs after the label:
Name: ____ - For radio groups, stack options within 30 pt of each other (vertical).
- Table cells with
[[ ]]are automatically sized to fit the cell.
FAQ
Is my PDF uploaded anywhere?
No. Your PDF is processed entirely inside your browser using WebAssembly. Nothing is sent to any server.
Which PDF editors work?
Any editor that exports a PDF with real selectable text: Microsoft Word, LibreOffice, Adobe InDesign, Google Docs, Apple Pages, etc. Scanned PDFs (image-only) will not work - markers must be real text characters.
Why were no fields added?
Check that your markers match exactly: [_] [o] ____ (four+ underscores) [[ ]]. Also confirm the PDF contains selectable text (not a scan). If you use different placeholder strings, configure them in the Markers tab before dropping your file. If no markers are found, the editor opens automatically so you can place fields manually.
Can I use different placeholder strings?
Yes - open the Markers tab and click the edit button on any row to change the marker string for that field type. For radio buttons you can also adjust the grouping distance and direction. For single-line text fields you can set the minimum number of repeated characters required, or leave it unset to detect a single character and use a fixed-width field. Settings are per-session; drop a new PDF or switch back to the Tool tab to re-analyse with updated settings.
Can I add or move fields that weren't in my original document?
Yes - click Edit fields after analysis to open the visual editor. You can drag existing fields to reposition them, resize them, add new ones from the toolbar, or delete any field before downloading.
How do radio button groups work?
Radio buttons marked with [o] that appear on consecutive lines within ~30 pt of each other are automatically assigned to the same group - only one can be selected at a time in the final PDF. Buttons further apart start a new group. The marker string and spacing threshold are configurable in the Markers tab. You can also assign groups manually in the editor by double-clicking a radio field.
Does it work offline?
Yes - after your first visit, FormMyPDF is cached as a PWA and fully functional without a network connection.
Is there a file size limit?
No hard limit, but files over 50 MB may be slow on mobile. You will be warned before processing begins.