Two factor recovery
Backup codes in a secure place known to executors; otherwise account recovery via providers with death processes
Some steps differ by region inside the country.
Where
Their authenticator app, printed backup codes, and the recovery options set on each account.
How
Keep their SIM active and in a working handset, many recovery flows send a code by text.
Look for printed backup codes, often kept with the will or in a safe.
Check whether the authenticator app was backed up to their cloud account, which makes the codes recoverable.
Where an account cannot be recovered, contact the provider's bereavement or deceased user team rather than trying repeatedly to log in.
What to bring
Their phone and SIM
Any printed backup or recovery codes
This is practical information, not legal, medical, or financial advice.