Medical coding is the process of translating healthcare diagnoses, procedures, and treatments into standardized codes for billing, insurance claims, and medical records. The main coding systems used are ICD-10-CM for diagnoses, CPT for procedures, and HCPCS for services covered by Medicare and Medicaid. Accurate coding ensures proper reimbursement, reduces errors, and maintains compliance with healthcare regulations. Coders must understand medical terminology, anatomy, and coding guidelines to perform their duties effectively. The field offers job stability, career advancement, and opportunities for specialization in various healthcare settings.