In newer version there is an "office icon" from which we can create this feature under "Option..".

But not sure what to do in word 2003.

You can create a document with form fields in Word 2003. Use the controls on the Forms toolbar (View | Toolbars | Forms). See also http://gregmaxey.com/word_tip_pages/...ormfields.html. Note that a simple form document doesn't require any macros.

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Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional