I purchased a phone from an individual and they are still longed into their Apple ID

You will have to contact the friend and have them do this→What to do before selling or giving away your iPhone, iPad, or iPod touch. Until they follow those instructions you will not be able to use the phone. As it’s a friend it should be no problem to fix one you explain it to them.

Your friend MUST remove Activation Lock from the phone or it will be useless to you. Send them this link and insist they do as directed or give the phone back to them for full refund --> What to do before you sell, give away, or trade in your iPhone, iPad, or iPod touch - Apple Support

And this -- The All Too Common SAD Reality of Buying … - Apple Community