By AutoFill you mean duplicating data from one field to others?
Repeating Data (Populating Multiple Like Fields)

Also look into Building Blocks & AutoText

Finally, look into the AutoTextList field. How to Add Pop-Up Lists to Any Word Document So You Can Click Your Way Through Changes in Seconds (or how to use the AutoTextList field) by Bill Coan, MVP

Here is my work in progress on AutoText. Automated Boilerplate Using Microsoft Word