How to make a PDF fillable, and when you don't need to

What is a fillable PDF?

A fillable PDF contains interactive form fields stored inside the file in a format called AcroForm. Text boxes, check boxes, radio buttons, drop-down lists, date fields and signature fields are all AcroForm field types. In a viewer the fields light up, you can tab between them, and what you type is saved inside the PDF. Tax forms from the IRS, job applications and most insurance forms work this way.

A flat PDF, by contrast, just shows lines and boxes as printed graphics. You can see where to write but there is nothing to click into. Many forms sent by email are flat, either because they were made in Word and exported, or because someone printed and scanned them.

Do you actually need to create form fields?

Before you learn a form designer, decide which of these describes your situation.

DocGopher's tools do not create AcroForm fields. If you need true fields, use one of the programs in the next three sections. Otherwise skip to the shortcut section.

• You received a form and need to fill it in and send it back. You do not need to make it fillable. Type on it with Edit PDF or any viewer's text tool, then save.
• You made a document in Word and want to send it to one person to complete. Sharing the Word file, or a PDF they can type on, is usually enough.
• You need to send the same form to many people, collect the answers and read them back reliably. This is where real fields pay off.

How to make a PDF fillable in Adobe Acrobat

Adobe Acrobat Pro (the paid version, not the free Reader) is the standard tool for building PDF forms. It can detect boxes and lines on an existing flat PDF and turn them into fields automatically.

Acrobat Pro is a paid subscription with a free trial, which may be all you need for a one-off form.

1. Open your PDF in Acrobat. From the Tools or All tools menu, choose Prepare a form.
2. Confirm the file and let Acrobat auto-detect fields. Underlined blanks and boxes become text fields, small squares become check boxes.
3. Review the result. Drag any field to fix its position, delete false detections and add missing fields from the toolbar.
4. Double click a field to name it and set options such as font size, multi-line text, a character limit or a required flag.
5. Save. The file is now fillable in Acrobat Reader, browsers and most viewers.

How to create a fillable PDF for free with LibreOffice

LibreOffice is a free office suite for Windows, Mac and Linux, and its Writer and Draw programs can place form controls on a page and export them as real PDF fields. It is the best free route to a true fillable PDF.

The exported PDF opens with working fields in Acrobat Reader, browsers, Preview and on phones. Turn on the grid under View to line controls up.

1. Open your document in LibreOffice Writer. If you only have a PDF, open it in Draw: each page becomes an editable drawing.
2. Choose Form from the menu bar (or View, Toolbars, Form Controls) and switch on Design Mode.
3. Pick a control, for example Text Box or Check Box, and drag it onto the page where the answer should go. Repeat for each blank.
4. Right click a control and choose Control Properties to name it and adjust the border, font and whether it can hold more than one line.
5. Choose File, Export As, Export as PDF. In the General tab, tick Create PDF form, leave the submit format as it is, then Export.

How to make a fillable form in Microsoft Word, and what happens on export

Word can build a form with its Developer tab, and this is the right tool if the people filling it in will use Word. It is a weaker route to a fillable PDF, for a reason explained below.

The catch: when you export that form as a PDF, Word flattens the content controls into plain text and boxes, so the PDF is not fillable. To get real fields, export the PDF and run Acrobat's Prepare a form auto-detection on it, or open the exported PDF in LibreOffice Draw and add the controls there.

1. Turn on the Developer tab: File, Options, Customize Ribbon, then tick Developer. On a Mac: Word, Preferences, Ribbon and Toolbar.
2. Place the cursor where an answer goes and insert a control from the Developer tab: Plain Text Content Control, Check Box, Drop-Down List or Date Picker.
3. Click Properties to give each control a title and placeholder text.
4. Choose Restrict Editing, allow only Filling in forms, and start enforcing protection. Now the text is locked and only the controls can be changed.
5. Save as a .docx and share it, or save it as a Word template (.dotx).

Online PDF form builders

Several web-based PDF editors add form fields in the browser, and most offer a free tier: open the PDF, pick a field type, drag it into place, download. Before you rely on one, check three things: the file size and page limits on the free plan, whether the download carries a watermark, and what the service does with your document after you upload it. Do not upload forms containing other people's personal data until you have read that policy.

The shortcut most people need: type on the PDF

If your real goal is to fill in a form that arrived as a flat PDF, or to send a document that one person can complete, you do not need form fields at all.

Edit PDF is free, needs no account, adds no watermark, and works on a phone as well as a computer. Files are processed in memory and deleted from the server after 30 minutes.

If you are building the document yourself, create it in Word online or Google Docs with clearly labeled blanks, then share it as a Word document or as a PDF people can type on with the steps above.

1. Open Edit PDF, linked above, and drop in the flat PDF.
2. Choose the Text tool, click on each blank line and type your answer. Match the font size to the form and drag the box to align it.
3. Tick a box by typing an X in it, or use the Draw tool to make a check mark.
4. Add your signature with Sign PDF if the form needs one, then download the finished file.

How to fill out an existing fillable PDF

When a PDF already has fields, you do not need any special software.

Always save a copy and reopen it to confirm your answers are still there; some browsers show your typing but do not keep it unless you use the download button.

• Chrome or Edge: open the PDF, click a field and type. Press Tab to move to the next one. Use the download or save icon to save a copy with your answers.
• Adobe Acrobat Reader (free): the most reliable choice for complex forms, especially government forms with calculations or signature fields.
• Mac: Preview fills fields and lets you add a signature from the Markup toolbar.
• iPhone or iPad: open the PDF in Files, tap a field to type. Use the Markup pen for anything without a field.
• Android: the Google Drive viewer and the free Acrobat Reader app both fill fields.

How to flatten a filled PDF and send it

A filled form still has live fields, so anyone who opens it can change your answers, and some viewers show the fields empty. Flattening converts the fields and their contents into ordinary page content, so the form looks the same everywhere and cannot be edited by accident.

Keep both versions: the fillable one in case you need to correct something, and the flat one for sending.

1. Windows: open the filled PDF, press Ctrl-P, choose Microsoft Print to PDF as the printer, and save. The output is flat.
2. Mac: open the PDF in Preview, choose File, then Print, click the PDF button at the bottom left and choose Save as PDF.
3. Any computer: open the PDF in Chrome, press Ctrl-P or Command-P, and set the destination to Save as PDF.
4. Check the file size. Printing to PDF can inflate scanned pages; Compress PDF brings it back down for email.
5. If the form holds a Social Security number, bank details or medical information, add a password with Protect PDF and share the password separately.