Simply put: Coverage describes what insurance will pay for.
1. INSURANCE is where you regularly pay money to a company and, in exchange, that company will pay for the cost of a bad thing if it ever happens.
Example: "I pay $100 per month in car insurance. Hopefully, I never get in a car accident! But, if I ever get in a car accident, the insurance will pay for a new car and all medical bills."
2. COVERAGE describes what your insurance will pay for.
Example 1: If I drink alcohol before driving and then get in a car accident, my car insurance offers no coverage. I will have to pay all medical bills and car fees myself.
Example 2: The health insurance my company offers does not include dental coverage. If I have a tooth problem, I will need to pay everything "out-of-pocket" (all by myself).