Unable to update my apps

Hey! I am hoping someone can help me with this...

My entire phone has always been synced to one icloud log-in, however I needed to factory reboot & used a friends computer. Ever since then I have been able to update my apps. As it keeps asking for someone else's password.

I have tried going through setting/App Store/forget sign-in & I've tried signing out then back in again. I've gone through what I feel is the entire general setting to re-due all my logins. But no where do I even find where this email address has been stored.

I'd really love to update my apps, help!