Final answer:
Block 1 on the CMS-1500 contains information about the type of health insurance coverage the patient holds, which is essential for correct claim processing.
Step-by-step explanation:
Block 1 of the CMS-1500 form is designated for the selection of the type of health insurance coverage the patient holds. This section is crucial because it determines how the claim will be processed by the payer. The options typically include choices such as Medicare, Medicaid, TRICARE, CHAMPVA, Group Health Plan, FECA Black Lung, and Other. It is important for the healthcare provider or billing specialist to accurately select the correct insurance type to ensure proper claim processing and reimbursement.