Using two-factor authentication helps prevent others from accessing your > [your name] > Sign-In & Security.
Tap Two-Factor Authentication, tap Edit (above the list of trusted phone numbers), then enter your device passcode when prompted.
Do one of the following:
Add a number: Tap Add a Trusted Phone Number, then enter the phone number.
Remove a number: Tap Sign in to your Apple Account.
Tap App-Specific Passwords, then tap “Generate an app-specific password.”
Follow the onscreen instructions.
After you generate your app-specific password, enter or paste it into the password field of the app as you would normally.
For more information, see the Apple Support article Two-factor authentication for your Apple Account