Before we go furher, read this:
Word for Wordperfect Users
You do not want to use the Word Fill-In or Ask fields. They are way too cumbersome for ordinary use.

What you are looking for here is a custom dialog box called a UserForm.
Create a Simple Userform
Create & Employ a Userform

By the way, template is a term of art in Word. To use a template properly, you double-click on it. This creates a new document based on (and attached to) the template. You can use an AutoNew macro to trigger the userform when this happens.
Templates in Microsoft Word