It's not really necessary (though it might be helpful). For important accounts (financial, mostly) there will be a policy and process for granting access to the estate upon presentation of acceptable proof of death.

A credit report will identify any open credit accounts and those creditors can also be instructed to provide payoff information and close the accounts.

The main thing you will need to handle the death are lots of certified copies of the death certificate. One per account, generally, and copies/digital scans are not accepted.