What he was asking is add the email to what?
There are many things and apps that one could use such info in.
We would need more information if we are gonna try to assist you.
If you are just trying to use an email app to check your email, then the app would have its own “Add account” option built in. For Yahoo, you may have to select “other account” and input the server and login info manually.
I am not sure what the default mail app is in Moto phones, probably gmail. That app does support other accounts.
What @cbwahlstrom was suggesting is the easiest and most straightforward solution, considering the info given, to install the Yahoo Mail app…if that what your end goal is…to check your Yahoo email.
I personally use a standalone maill app, TypeMail, that supports pretty much every account type out there.