How to Set-Up a New iPhone When the Old iPhone is Dead

If her phone number has not changed she will be able to use the new phone to verify 2 factor authentication. However, the only way to get data off the dead phone is to restore a backup she made before the phone died.

Can the old phone be used if it is plugged in? Most phones with a dead battery will still work if plugged in; if heres does then she can transfer data from it.

This leads to two suggestions:

1. Log in to https://appleid.apple.com and add other trusted numbers to her security settings (perhaps your phone number, or a landline)
2. Start a regular schedule of backups. Ideally, go to Settings/[her apple ID name]/iCloud and turn on iCloud Backup, then plug in the phone overnight, every night, and it will back up automatically every night.

Did your wife use iCloud to backup her now dead iPhone? If she did, as long as the phone she wants to move to is ready for a new user and opens to the Hello page, she would sign into the new phone using her Apple ID and it will offer the opportunity to set it up from an iCloud backup.

Is the iPhone she will be moving to opening to the Hello page? It needs to be prepared appropriately for a new user and this is how that would be done --> What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support

Then see this link about setting up the phone once it's fully prepared and choose iCloud --> Transfer data from your previous iOS or iPadOS device to your new iPhone or iPad - Apple Support

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