You need to follow below steps to change phone number on my email account:
- First Sign in to your Account Info page.
- Click on setting Icon
- Click on “Accounts” button from the drop down menu
- Click the “Edit your account info” tab.
- Again, click sign in button
- Click on “Account security”
- Click on ->phone number->Add recovery phone number
- Add another Mobile Number then click “save”
- After that verify the new number by yahoo verification code
- Finally, Delete the old number and click the “save” button.
Call email customer service toll free number +1-844-444-0101 for a further assistant if needed.