Filling PDF Forms
By the Syncfusion DevTutorials team · Last updated
Fill in fillable PDF forms: text fields, check boxes, option buttons, and drop-down lists, then submit the form and save your completed copy.
Many organizations share forms as PDFs. Some PDF forms have fillable fields, which let you enter answers on screen instead of printing the form and writing by hand. This lesson shows you how to fill in text fields and choose answers from check boxes, option buttons, and drop-down lists. You'll also learn how to spot required fields, submit a form when that option is available, and save a copy of your answers.
You'll practise on a library membership form. Open it with Open the practice PDF in the exercise below.
Fillable and flat forms
There are two kinds of PDF form, and they look almost the same:
| Fillable form | Flat form | |
|---|---|---|
| What it is | The PDF has interactive form fields: boxes you can click and type into | The PDF has no interactive form fields; its boxes and lines are part of the page |
| How you fill it | Click a field and type | Print and write by hand, or place text on top of the page |
| How to tell | Fields are highlighted or bordered; the pointer becomes an I-beam over a box | Clicking a box does nothing |
In the sandbox and most PDF apps, fillable fields show a border or a colored background. If a form has no interactive fields, use Edit Annotation > Free Text to place text boxes over the page, or ask the sender for a fillable version.
Kinds of form field
Here are the five kinds of field you'll meet, and how each one is filled:
| Field | Looks like | How to fill it |
|---|---|---|
| Text field | A box | Click and type |
| Multi-line text field | A tall box | Type several lines; press Enter for a new line |
| Check box | A small square | Click to tick; click again to untick. Tick as many as apply |
| Option buttons (radio buttons) | Small circles in a group | Click one: choosing another clears the first |
| Drop-down list | A box with an arrow | Click and choose one option |
Enter text fields
Text fields are the most common, so start with them:
- Click in the first field.
- Type your answer.
- Press Tab to move to the next field (Shift + Tab goes back).
Tab follows the order the form's author set, usually top to bottom, so you can fill a whole form without touching the mouse. Check each answer as you go: spelling mistakes in an email address mean the reply never reaches you.
Some fields expect a particular format, such as a date written 14/03/2026, or a limited number of characters. Follow the hint next to the field, if there is one.
Select check boxes and options
The other kinds of field choose answers instead of typing them:
- Check boxes are for yes/no answers and lists where several answers can apply: "Tick every day you're available".
- Option buttons are for choosing exactly one answer from a group: "Card type: Adult, Child, or Senior".
- Drop-down lists also choose one answer, from a longer list that would take too much space as option buttons.
Required fields
Whichever kind of field it is, some are marked as required. Fields marked with an asterisk (*) are required: the form can't be submitted until they're filled in. In the sandbox, empty required fields have a red border. Fill them all before you submit.
Read the whole form before you start. Look for the asterisks, any instructions at the top, and fields on the next page: many forms go on longer than the first screen.
Submit forms
After filling in the form, the next step is to submit it or send it back. Some forms have a Submit button, or the viewer's toolbar shows Submit Form. Submitting sends your answers straight to the organisation, usually to a web address the form's author set up. If any required field is empty, the form tells you and nothing is sent.
Other forms ask you to email or upload the completed PDF instead. In that case, save the form (below) and attach the file.
The sandbox's Submit Form checks your required fields and reports the result at the top of the sandbox, but doesn't send anything anywhere: there's no real library on the other end.
Save the completed form
Whether you submit, email, or upload the form, keep a copy for your own records. Your answers live in the viewer until you save them into a file:
- In the sandbox and web browsers: click Download file. The downloaded PDF contains your answers.
- In Adobe Acrobat Reader: File > Save (or Save As, to keep the empty form too).
Then open the saved file to check your answers are all there before you send it.
Keep a copy of every form you submit, especially applications, tax forms, and anything with a deadline. If there's a question later, you can show exactly what you sent.
Common mistakes
| Mistake | What happens | How to fix it |
|---|---|---|
| Closing the tab before saving | Your answers are lost | Download first, then close |
| Two option buttons wanted | Clicking the second clears the first | That question allows only one answer |
| Empty required field | The form won't submit | Look for red borders and * |
| Typing on a flat form | Nothing happens | Use Free Text, or ask for a fillable form |
| Wrong date format | The form or the reader misreads it | Follow the format shown next to the field |
Exercise
Here is your chance to fill in a real form yourself.
Click Open the practice PDF below to open the Library Membership Form. Fill it in for a new member, Alex Morgan. Do each task and press Check.
What to remember
- Fillable forms have real fields; flat forms are pictures (use Free Text or paper).
- Click a field and type; Tab moves to the next field.
- Check boxes: tick all that apply. Option buttons and drop-down lists: choose one.
- * marks a required field; empty ones block submitting.
- Submit Form sends the answers (when the form has a destination).
- Download (or Save) to keep your completed form, and keep a copy.
In the next lesson, you'll sign PDF documents electronically.