Yahoo Mail app was preloaded on my Samsung Galaxy s3 MIni. (I think, or maybe I downloaded it.) I suppose when I first used the app I had to sign in with my e-mail id and password. However now when I open the app it goes straight to my inbox. No signing in is required. Should I lose my phone then anyone could access my e-mails. How do I set the phone so that a password is required to get into my e-mails. Or anyother suggestions to stop unauthorised persons getting at my e-mail.