The beneficiary contacts the insurance carrier to advise them that a person insured by one of their life insurance policies has died.
The insurer will advise the beneficiary what to do - usually you will need to complete some paperwork regarding the claim (which is mailed to the beneficiary from the insurer) and send that back to the insurance company along with an original death certificate of the insured person who has passed away.
Payments on death claims are usually mailed to the beneficiary within 10 to 15 days after the insurance company has received all necessary paperwork.