VOIDED CHECK or BANK LETTER. 1. Attach an original voided check or bank letter (in banks letterhead) to the completed enrollment form.SDCCU offers overdraft protection, account alerts, wire transfers, safe deposit boxes and more. We will cover how to properly fill out an ACH form and how to submit the additional information required. To get your direct deposit started, fill out the form below and return it to your payroll department. There are several enrollment options: 1. Enroll customers in lobby, batch and submit ENR enrollments through ACH from the financial institution. ACH Interest Payment Authorization. Fax Number 1-858-350-0443. ACH Interest Payment Authorization.