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Fillable PDF vs flat PDF, explained
If you have ever wondered why one PDF lets you click and type while another ignores you completely, the answer is the difference between a fillable form and a flat one. Understanding it makes every future form easier.
Fillable (interactive) PDFs
A fillable PDF contains real form fields — technically called AcroForm fields — that the author defined: text boxes, checkboxes, dropdowns. Your viewer knows exactly where you are allowed to type because those fields are part of the file. These are the friendly ones.
Flat PDFs
A flat PDF has no fields. It is a static page — often exported from a word processor or a design tool — meant to be printed and filled by hand. Clicking on a line does nothing because, as far as the file is concerned, there is nothing there to click.
Scanned PDFs
A scan is the most static of all: a photograph of paper wrapped in a PDF. There is no text and no fields, only an image. Filling it requires a tool that can look at the picture and work out where the answers go.
How to fill each one
- Fillable: click a field and type — most tools handle this.
- Flat: you need a tool that adds text on top of the page. Formagator detects the printed lines and boxes and places fields for you.
- Scanned: you need layout detection plus on-device OCR to read labels. See filling a scanned PDF.
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Frequently asked questions
How can I tell which type I have?
Try clicking a blank line. If a cursor appears, it is fillable. If nothing happens, it is flat or scanned.
Can a flat PDF be turned into a fillable one?
Effectively yes — Formagator overlays fillable fields onto flat pages, then flattens your answers on export.