Complete and submit the attached ACH Authorization Form. The CSU, Office of the Chancellor strongly encourages the use of electronic payments via ACH.A bank letter is an official document from your bank that provides important information about your business' official bank account. How Do I Obtain an ACH Authorization Form? The routing number from a deposit slip is invalid. Your California Department of Tax and Fee Administration (CDTFA) account number is required (for example, 044-123456). Complete the attached ACH Authorization form. 2. Attach a voided check OR a signed bank letter (on bank letterhead) for verification of all banking information. 1) Ensure entire form is complete, then sign and date. Send us your Nacha-formatted file directly from your accounts payable system or upload it using Treasury Internet Banking for straight-through processing.