Forum Discussion
How to create a document with fill in the blank line?
[Best method for most situations] Use Content Controls.
You could use a MacroButton Field instead. (despite name, this use does not use macros)
To have other text not move, you would want to have your variable content inside a table cell that does not change size.
On my Mac Office 365 Word I have developer mode but not seeing the same options as explained in the article.
https://gregmaxey.com/word_tip_pages/content_control_fillin_form.html
You didn't mention that you were using a Mac. That makes a difference because they are different programs even though they edit the same document files and look much the same.
Compare Word features on different platforms - Office Support
The Mac does not have Content Controls unless you develop the form in Word. They work on the Mac, though. See Content Controls for macOS by John Korchok.
Here is a document with Content Controls you could copy into your form if you want.
Mac Content Controls Document - Experimental
However, since you can't edit them on the Mac I do not know it will help you.
You can use the form fields on the Developer Tab on the Mac. You then have to lock/protect the form. Same design principles apply.
You can also use the MacroButton Fields as Prompts on the Mac.
