[AC Question]

I have an email account from yahoo I want to sign out but don't know how

[rcunningham]

I have an email account from yahoo I want to sign out but don't know how

What app are you using?

[anon8380037]

On the stock Email app and Yahoo app you cannot, and Yahoo or any via the Gmail app, but there may be other email apps that allow you.
People mostly rely on a secured Lock Screen, although I personally don't use one.
If need be you could delete your account and restart it just with a name and password. Depends if you only use a small inbox. (is that a dumb idea?)

[Rukbat]

Do you mean sign out, as in not currently connected? That's easy - close the app. Of course if you open the app again, it signs you back in. (And if you have syncing enabled for that account, disabling it will keep the app from signing in to sync.)

Or do you mean sign out as in no longer have the account? That depends on the email provider, but Yahoo probably provides a way to close the account.