Go to Settings > Apple ID > Account Recovery and follow the steps.
You can also turn on Recovery Key to get a 28-character code to recover your data.
How to Add a Recovery Contact in case you forget your password
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Do a Safety Check
Go to Settings Privacy and Security Safety Check Click Manage Sharing & Access.
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6 iPhone Security Settings to Protect Your Data
How to set up recovery contacts, Face ID, iCloud backup, and manage subscriptions on iPhone