I agree 100% with Andrew's response.

If the UserForm is too much for you to tackle right now, look into the AutoTextList field. This is older, very stable, technique. It does not require any vba programming. It will work in any version of Word beginning with Word 97, at least.

• AutoTextList field - How to add pop-up lists to any Word document, so you can click your way through changes in seconds
• Automated Boilerplate Using Microsoft Word

If you are up to it, though, a userform is far more powerful.

• Create & Employ a Userform
• Create a Simple Userform

If you are doing much template design userforms are worth investing the time to learn.
See also Templates in Microsoft Word.