How to add check boxes, dropdowns and date fields to a PDF form

A form is only as good as its questions, and a question is only as good as the box it gives people to answer in. A free-text line where a tick would do invites "yes, mostly". A dropdown of forty countries is easier than making people type one. Here is how to choose, and how to add each field type to a PDF.

Choose the field by the answer you want

To add any of them, open your PDF in PDF Forms, pick the type on the left, then click on the page to place it or drag to draw its size. The type stays selected, so you can place several in a row; press Esc when you are done.

Text fields and paragraphs

A text field is one line; a paragraph wraps onto several. The settings that make them work well:

• Character limit. Stops an answer at a set length, useful for codes and reference numbers.
• One letter per box. Spreads the text evenly over a row of boxes, like a code or an account number printed in separate squares. It needs a character limit first, one per box.
• Stop at the edge of the box. By default a long answer scrolls inside the field. Tick this and it cannot go past the visible width, so what is printed matches what was typed.
• Text size. Auto shrinks the text to fit the box. A fixed size keeps every answer the same.
• Font and alignment. Helvetica, Times or Courier; left, centre or right.

Check boxes and choice buttons

These look alike and behave differently, and mixing them up is the most common form mistake.

Check boxes are independent. Each one is ticked or not, whatever the others do. Use them for "tick all that apply" and for single statements like "I agree to the terms". Each box can store its own value when ticked, and can start ticked.

Choice buttons, often called radio buttons, come in groups. Choosing one clears the others, so only one answer is possible. Place the first button, then place more straight away to add them to the same group. Each button has its own value, which is what the form stores when that button is chosen, and one button can be chosen to start with.

Dropdowns and list boxes

Both offer a list of options. Type them one per line, or paste a whole list at once.

Each option has two parts: the label people see, and the value the form stores. They are usually the same, but they do not have to be. Show "United Kingdom" and store "GB", for instance.

A dropdown takes one line on the page and opens when clicked. Tick Allow typing another answer if people may write something that is not on the list.

A list box shows several options at once. Tick Allow several choices to let people pick more than one.

Date fields

A date field is a text field that knows it holds a date. Choose one of five formats: dd/mm/yyyy, mm/dd/yyyy, yyyy-mm-dd, dd.mm.yyyy or d mmm yyyy.

PDF apps that support form checks, such as Acrobat and Reader, reformat and check the date as it is typed. Apps that do not run form checks treat it as an ordinary text field, so people can still type a date; it just is not checked.

Signature fields

A signature field marks the place where a real digital signature goes. It can be signed in Acrobat and other PDF apps that support signing. Each signature field, like any field, can also note which signer should fill it in, which is kept in the PDF so the form can be sent through Request Signatures later without placing its fields again.

A signature field is different from pasting a picture of your signature with Sign PDF. Why the difference matters is explained in why a picture of a signature is not a signature.

Settings every field has

• Field name. The name other programs see, for example when answers are collected from returned forms. Keep it short and clear.
• Help text. Shown when someone points at the field. Good for "as shown on your passport".
• Required. PDF apps that support form checks warn before a form is sent with this field empty.
• Read-only. The field is shown but cannot be changed. Useful for a pre-filled reference number.
• Starting value. What the field contains before anyone types.
• Colours and border. Text colour, fill, and a solid, dashed or underline border.

Copies and linked copies

Duplicate a field and you get a choice. A copy is a new field with its own name and its own answer. A linked copy has the same name, so whatever is typed in one appears in the other. Use a linked copy for a name that should appear at the top of every page but only be typed once.

Test before you send

Press Try the form and fill it in the way your readers will. Tab through it to check the order. Show what is missing points out required fields still empty. Nothing you type in the preview goes into the file.

For the full workflow from a plain PDF, see how to make a PDF fillable.