Health insurance is a type of coverage that pays for medical and surgical expenses incurred by the insured individual. It can also provide coverage for other types of health-related expenses, including prescription drugs, preventive care, and mental health services. Health insurance is designed to protect individuals and families from the financial burden of unexpected medical costs.

Key components and features of health insurance include:

1. **Premiums:** Insured individuals pay regular premiums to the insurance company to maintain coverage. Premiums can be paid on a monthly, quarterly, or annual basis.

2. **Deductibles:** The deductible is the amount an insured person must pay out of pocket for covered medical expenses before the insurance company starts to pay. For example, if a policy has a $1,000 deductible, the insured individual must pay the first $1,000 of covered expenses before the insurance coverage kicks in.

3. **Co-payments and Co-insurance:** After reaching the deductible, individuals may still be responsible for co-payments (a fixed amount for certain services) or co-insurance (a percentage of the cost of services). These out-of-pocket costs are shared between the insured and the insurance company.

4. **Coverage Limits:** Health insurance policies often have limits on the total amount they will pay for certain services or over a specific period. This can include an annual limit or a lifetime limit for particular types of care.

5. **Networks:** Insurance companies often have networks of healthcare providers, including doctors, hospitals, and other facilities. In-network providers typically have negotiated rates with the insurance company, resulting in lower out-of-pocket costs for the insured individual.

6. **Preventive Care:** Many health insurance plans cover preventive services at no cost to the insured individual. This can include vaccinations, screenings, and other services aimed at preventing or detecting health issues early.

7. **Prescription Drug Coverage:** Health insurance plans may include coverage for prescription medications, either with co-payments or co-insurance. Formularies, which list covered drugs, may vary among plans.

8. **Types of Plans:** Health insurance plans come in various types, including Health Maintenance Organization (HMO), Preferred Provider Organization (PPO), Exclusive Provider Organization (EPO), and High Deductible Health Plan (HDHP) with Health Savings Account (HSA), among others. Each type has its own features and restrictions.

9. **Marketplace Plans:** In some countries, health insurance can be purchased through government-run health insurance marketplaces. These marketplaces offer a selection of plans that meet specific coverage standards, and individuals may be eligible for subsidies based on their income.

10. **Employer-Sponsored Insurance:** Many individuals obtain health insurance through their employers. Employer-sponsored plans may cover the employee and, in some cases, their dependents.

Having health insurance is essential for managing healthcare costs and accessing necessary medical services. The specific details of a health insurance plan, including coverage, costs, and limitations, can vary widely, so it’s important for individuals to carefully review and understand their policy terms.