UB04 Hospital Claim Form Imprinted Window Envelopes (1000/case) White Envelopes are imprinted with the return address you choose Includes a sized window on the left side to show payor's address Designed for UB-04 claim forms ( known as CMS 1450 claim forms) One easy fold (Fold UB04 claim form in half) Instruction: 1)Order and pay for item. 2) Send us an email with return address to be printed. 3) Include phone number in email just in case of any issues