1) Open your Yahoo app on your phone.
2) At the top, tap on the options icon to the left of the of the word INBOX.
3) Stroll down to PEOPLE icon, and tap.
4) Tap “SHOW ALL CONTACTS”
Ive tried several different apps for yahoo mail and no place to access contacts. And the mail app saves all the outgoing email address in the app but no way to clean it out.