Tap your email address from the menu.
ChooseAllowon the prompt about saving your codes to your Google account.
Export the 2FA Codes
Another way this works is by exporting the accounts.

You’ll see a QR code.
From the new phone, go tomenu>Transfer accounts>Import accounts>Scan QR code.
Point the camera at the QR code on the old phone.

You’ll see a success message indicating how many accounts were copied over; tapOK.
At this point, you’re done and can close both apps.

