Life insurance pays a face amount or benefit to your estates (debt, mortgage, student loans, auto loans, …etc). When you get a life insurance policy you are proactively protecting your beloved ones from incurring your debt.
You can buy, purchase, or own a life insurance policy if you are 18 years or older. Some carriers and certain insurance plans have a minimum age and a maximum age on specific policies or benefit amounts.
General rule, the younger you are the cheaper the policy. You can get a Term Life Insurance policy for 10, 20, or 30 years with guaranteed renewal or with cash value that you make back when you surrender the policy or the term is over.
Or you can get a Whole Life Policy, that remains effective as long as you are alive with level (never change) premiums. There are some policies that have an investment component in them where part of you premiums is invested in the market at a fixed or variable interest to accumulate additional cash value which you can loan or withdraw from during your life.