Set Up Your HSA Account Complete the Form Download and complete the HSA set-up form with Interra Credit Union. Fax or mail the form to the contact information located at the bottom of the PDF. Download the Form Open an Account Call Interra at (574) 534-2506 or (888) 432-2848 to open your account once the set-up form has been completed and submitted. Share Your Account Number Once your account is open, notify the Goshen benefits team with your Interra-provided account number so that contributions can begin.