Yes, but not easy on a Mac.

1. You can use an AutoTextList drop down. AutoTextList field - How to add pop-up lists to any Word document, so you can click your way through changes in seconds
2. You can use a dropdown field in a protected form using the Developer Tab. (does not allow anything other than listed choxces, though) Making Forms with Microsoft Word
3. You can use a ComboBox dropdown Content Control but you will have to program it or create your form in Word for Windows. Content Controls for macOS by John Korchok
4. You could use a Building Blocks Gallery Content Control with the AutoText (see previously linked article) Building Blocks Gallery Content Control and AutoTextList Field Comparison and Demonstration

For letter forms, see also: Setting Up Letter Templates - Ribbon by Suzanne Barnhill, MVP