Approve and Decline buttons with the Agreement Template builder.

We want to create a template with word document and the sender text tags will have values varying from 10 to 50 characters, so we tried using Agreement Template Builder but Approve and Decline buttons are not available. If we use classic editor, we can have Approve and Decline buttons, but the content is the word document is static. If the word document content is static and in the sender text tags is having less characters, empty space is visible and when the characters are more, text is overlapping on the content.