Is there a way to replace the Background/master PDF without losing any of the text fields that I have set up?

There are two way to change the Master PDF without losing the fields and its position on the e-Doc Builder Template:
 
  1. Upload a New Master PDF with the fields with same name and same position.
  2. Use field Designer to create a Background field, keep its stacking order lower than the other fields on the template and then upload a new artwork (PDF) as a Graphic file. This will allow the user to see an updated background with the same fields at same position.