Keep a valid mobile phone number or email address on your account in case you ever lose your password and remove them from accounts you don’t recognize or use.
https://help.yahoo.com/kb/SLN2058.html

Keep a valid mobile phone number or email address on your account in case you ever lose your password and remove them from accounts you don’t recognize or use.
https://help.yahoo.com/kb/SLN2058.html