FormForge

FormForge turns a flat PDF into a fillable one without leaving the browser. Load a document and press Detect fields: it looks for the places a reader is meant to write, the ruled lines, boxes and dotted underscores, and proposes fields there. From that starting point you move, resize, rename, retype or delete anything, and add the ones it missed by hand. Text, checkbox, radio, dropdown, signature, date and number fields are all available, each with its own properties panel for name, tooltip, required and read-only flags, position, size and default value.

The export is an ordinary AcroForm PDF: it opens and fills in Acrobat, Preview, Chrome, Firefox and mobile PDF apps, with no dependency on FormForge afterwards. There is also a set of AcroForm checks with one-click fixes for the structural problems that make a PDF open badly in one reader and fine in another.

The whole thing runs client-side. The PDF is parsed and rewritten inside the tab and is never uploaded, so it works offline and documents holding personal or contractual content stay on the machine they came from. Drafts live in the browser's own storage. There is no account, no install and nothing to cancel. It was built for the recurring small chore of being handed a PDF that was clearly designed to be printed and signed, an intake form, a rental application, a school permission slip, and wanting to fill it in properly instead of printing, writing and scanning.