Add Mobile Number in Gmail/Google Account:
Add or change a recovery phone number
On your Android phone or tablet, open your device’s Settings app then Google and then Google Account.
At the top, tap Security.
Under “Ways we can verify it’s you,” tap Recovery phone. You might need to sign in.
From here, you can:
Add a recovery phone.
Change your recovery phone: Next to your number, select Edit.
Delete your recovery phone: Next to your number, select Delete.
Follow the steps on the…