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Free PDF Form Filler

Fill in an interactive PDF form and optionally flatten it so the answers can't be edited. Runs entirely in your browser — the document is never uploaded.

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Your files never leave your device. All processing happens locally in your browser.

Fill in a PDF form, then optionally flatten it so the fields can't be edited again. Everything happens in your browser — the PDF is never uploaded.

Common uses

  • Fill a Tax FormComplete an official tax PDF and lock it before submitting.
  • Complete an Application FormFill in a job, rental, or school application PDF.
  • Fill and Lock a ContractComplete a contract's fields and flatten it before sharing.
  • Flatten a PDF FormLock a completed PDF form so its fields can no longer be edited.
  • Fill a Form You Use OftenQuickly complete a recurring PDF form without Acrobat.

How It Works

Acrobat charges for filling and flattening forms, and iLovePDF gates flatten behind a sign-up. This fills interactive PDF forms and flattens them with pdf-lib, entirely in your browser.

  1. 1
    You drop in a fillable PDF
    The form fields (AcroForm) are read locally with pdf-lib — text boxes, checkboxes, dropdowns, radio buttons.
  2. 2
    You fill in the fields
    Each field is shown as an editable input, pre-filled with any existing value. Nothing is uploaded.
  3. 3
    Values are written back
    Your answers are written into the form. Optionally, the form is flattened — baking the values into the page so they can't be edited.
  4. 4
    You download the result
    The filled (and optionally flattened) PDF is offered for download.

Forms hold personal data — tax info, applications, contracts. Filling them on a server means uploading all of it. Here everything stays on your device, and flattening ensures recipients can't alter your answers.

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Frequently Asked Questions