How to use the Fill PDF Form tool
- Choose the PDF form. PaperKit reads it and tells you how many fillable fields it found and on which pages.
- Type your answers in the Form fields list, or click a box on the page preview and type there. Tick checkboxes and pick choices the same way.
- For a form that is only printed lines, press Add text box, type your answer in the panel and drag the box onto the line.
- Tick Flatten the form if the answers should become part of the page, for example before you email it.
- Press Fill and download PDF and check the preview of the result.
Worked example: an application with four fields
An application PDF has 4 fillable fields on page 1: a text field for the name, an I agree checkbox, a plan choice with the options basic and pro, and a country dropdown with Canada, Mexico and United States. PaperKit lists all 4 under Page 1. The applicant types Jane Doe, ticks the checkbox, picks pro and chooses Mexico. Downloaded without flattening, the file still has 4 fields, now holding those answers, and can be changed later in any PDF viewer. Downloaded with Flatten the form ticked, the result has 0 fields, and Jane Doe is ordinary text on the page that can be searched and printed exactly as shown.
Fillable forms, flat forms and flattening
A fillable PDF contains interactive AcroForm fields that a viewer draws as boxes. PaperKit saves your values into those fields, so the form stays fillable: the next person, or you, can still change an answer. Flattening merges the answers into the page. That is useful when you send a finished form, because some viewers and printers ignore field values, and it stops anyone from editing your answers. Keep an unflattened copy if you might need to correct something.
Many forms are just scans or printed lines with no fields at all. Typewriter mode handles those: each text box is drawn onto the page in Helvetica, the font every PDF viewer has.
Limits worth knowing
The standard PDF font covers English and most Western European letters, but not emoji or scripts such as Chinese, Arabic or Cyrillic; you will see a clear message if a value cannot be drawn. Forms built only with XFA, an older Adobe format used by some government agencies, may show no fields; when a file has both XFA and normal fields, the XFA part is removed so every viewer shows your answers. Signature fields are listed but not filled here: use the Sign PDF tool for those. Password-protected forms must be unlocked first.
Your files stay on your device
Forms are often full of personal details: your address, date of birth, income or medical history. Here the PDF is read and filled by code running in your own browser, in a background worker. Your answers are never sent to a server, and nothing is stored once you close the page.
Frequently asked questions
Why does it say no fillable fields were found?
The PDF is a flat document, such as a scan or a form printed to PDF. Use typewriter mode: add text boxes and drag them onto the lines.
What does flatten do?
It turns the fields into normal page content. Your answers look the same, but nobody can change them in a viewer, and every printer shows them.
Can I fill the form on my phone?
Yes. The field list works well on small screens, and you can also tap a field on the page preview and type.
Are my answers saved anywhere?
No. They exist only in this tab until you download the PDF. Closing or reloading the page clears them.
Can I sign the form too?
Yes. After downloading, use the Sign it shortcut to open the filled form in the Sign PDF tool without choosing it again.