Fill interactive AcroForm fields in your PDF files online for free with our Fill PDF Forms tool. Automatically detect text boxes, checkboxes, dropdown menus, and radio buttons, complete form entries, and optional form flattening in client browser RAM.
Upload an interactive PDF form or document with fillable form fields.
Type text responses, select checkboxes, radio options, and dropdown selections directly.
Click Save Form to flatten field values into the PDF structure and download your completed file.
Scans internal PDF form dictionary trees, extracting text fields, checkboxes, dropdown lists, and radio buttons automatically.
Optionally flatten form fields to convert interactive inputs into immutable static text and graphics in the output PDF.
All form parsing, field mapping, and PDF stream modifications execute inside client browser memory. Zero files leave your device.
Interactive PDF forms maintain an /AcroForm catalog dictionary entry containing arrays of field terminal objects (/Fields). Each field defines field types (/FT: text, button, choice), field names (/T), field values (/V), and default appearance string streams (/DA).
When parsing loaded forms, loadedPdfDoc.getForm().getFields() enumerates interactive terminal widgets and maps user inputs to field constructors (PDFTextField, PDFCheckBox, PDFDropdown).
When the "Flatten Form Fields" option is enabled, calling form.flatten() burns active widget appearance streams into static page vector graphics and removes interactive field dictionary annotations, creating an uneditable final document stream.