Health Maintenance Organizations (HMOs) are a type of managed care health insurance plan that provides a range of medical services to members for a fixed monthly fee. Members typically choose a primary care physician (PCP) who coordinates their healthcare and refers them to specialists when necessary. This model emphasizes preventive care and aims to reduce overall healthcare costs. HMOs often require members to use a network of doctors and hospitals to receive full benefits. If members seek care outside this network without a referral, they may have to pay higher out-of-pocket costs. This structure helps control expenses while promoting efficient healthcare delivery.