In Copr, we have at least one person each week who is confused about where to put OTP in the auth form. I think there are two reasons for this (which we found when investigating the issue with the person).

The login form on https://accounts.fedoraproject.org/ has three fields (Username, password, and OTP) while the login form on https://id.fedoraproject.org has only two (Username and password + OTP)
The login form on https://id.fedoraproject.org clearly shows that the field is password + OTP but it is indicated only in the field placeholder and therefore people who auto-fill the form don't see this information.
I don't know what is the preferred solution for this, whether adding the third field for OTP as https://accounts.fedoraproject.org/ does or displaying that the field is password + OTP somewhere (else) outside the field placeholder. Either one is fine with me but the current situation seems to be not sufficient.

Originally reported here
https://github.com/fedora-infra/noggin/issues/715