Primary care billing involves the billing and coding process for medical services provided by primary care physicians, such as routine check-ups, preventive care, and basic treatment for common illnesses. It includes tasks such as capturing patient information, assigning accurate medical codes for primary care procedures, and submitting claims to insurance companies for reimbursement. Primary care billing requires expertise in coding guidelines for primary care services, understanding of insurance policies, and compliance with regulatory requirements to ensure proper reimbursement and optimize revenue in primary care practices.