Health insurance is a type of insurance coverage that pays for medical and surgical expenses incurred by an insured individual or group. It helps protect against high medical costs by providing financial assistance for medical services, prescription drugs, hospital stays, and other healthcare-related expenses.

Here are some key points about health insurance:

1. Coverage: Health insurance policies vary, but they generally cover a range of healthcare services such as doctor visits, hospital stays, prescription medications, preventive care, and sometimes dental and vision care. The specific coverage will depend on the policy and the insurance provider.

2. Premiums: Health insurance requires regular premium payments. Premiums can be paid by individuals, their employers, or a combination of both, depending on the type of insurance coverage. Premiums may vary based on factors such as age, location, type of plan, and the number of individuals covered.

3. Deductibles: Many health insurance plans have deductibles, which is the amount that an individual must pay out of pocket before the insurance coverage kicks in. For example, if you have a $1,000 deductible, you would need to pay $1,000 for covered services before the insurance starts paying.

4. Co-payments and Co-insurance: Co-payments (or co-pays) are fixed amounts that individuals must pay for specific services, such as doctor visits or prescription medications. Co-insurance is a percentage of the cost that an individual must pay for covered services. For example, if your co-insurance is 20%, you would pay 20% of the cost, and the insurance company would cover the remaining 80%.

5. Networks: Many health insurance plans have networks of preferred healthcare providers. These networks include doctors, hospitals, and other healthcare professionals who have agreed to provide services at discounted rates to the insurance company's members. It's important to check if your preferred healthcare providers are included in the network of the insurance plan you choose.

6. Pre-existing Conditions: Health insurance providers typically cover pre-existing conditions, which are medical conditions that you had before obtaining the insurance. However, there may be waiting periods before the coverage for pre-existing conditions begins.

7. Types of Health Insurance: There are different types of health insurance, including employer-sponsored insurance, government-sponsored programs like Medicare and Medicaid, individual plans purchased on the healthcare marketplace, and supplemental insurance plans.

It's important to carefully review and understand the terms and coverage of a health insurance policy before purchasing it. Additionally, health insurance requirements, regulations, and options may vary depending on the country you are in.