Where do I find the account number for my AT&T Prepaid account?

According to https://www.att.com/support/article/my-account/KM1022998/ I'm supposed to go to Profile > Sign-in info. Scroll to My linked accounts.  There is no Profile menu when I log in, but there is "Profile & Settings".  However, there is no "Sign-in info" selection on that screen, nor am I able to locate "My linked accounts."