Internal medicine billing involves the billing and coding process for medical services provided by internal medicine physicians, who specialize in the comprehensive care of adult patients. It includes tasks such as capturing patient information, assigning accurate medical codes for internal medicine procedures and treatments, and submitting claims to insurance companies for reimbursement. Internal medicine billing requires expertise in coding guidelines for internal medicine diagnoses and interventions, understanding of insurance policies, and compliance with regulatory requirements to ensure proper reimbursement and optimize revenue in internal medicine practices.