Uncle gave me iphone. How do I erase everything and connect it?

Okay what I would like to know most is how do I delete everything. He still has his photos and his email on it. He wants me to send the photos so in going to turn on the Wi-Fi (haven't yet) and send them all to him on fb. But his phone is still connected to his account and iCloud.
Do I just connect it to my computer? I'm really scared I'm going to delete all his emails or something XD it was his work phone so his email on there's extremely important and I just keep gettingm worried if I delete everything something will happen to his emails.
Will I be okay? Do I just plug it in and put my own account?
He had a new one now but this one still gets his emails as well as the new one.
I want to connect it to my account.
Please let me know how I can do that. After that I will call my cellphone company so they can connect it for me I just don't know how to delete everything without deleting something of his and how to put my account instead of his.

Iphone app stays half visible on screen after closed?

I noticed that my iphone 6 ios 8.3 has the an app that has been used previously still visible on the screen like half visible. I tried to restart my phone seceral times but it's still there. What can i do to fix this problem?

Is this free iphone giveaway real?

Is this free iphone giveaway real?

Added (1). is this free iphone giveaway real? Or just scam?
its very professional and good looking site do you think its scam or real?
http://cf6.co/5uJL

IPhone dead and will not charge?

My iPhone 4 has been dead for about a month now and I needed to charge it because I'm trying to recover something with my old phone number… When I plug it into the mains it just stays on the battery with charge screen… Any help with my trying to fix this or whether I will have to take it to a shop

Live photos on iphone 6 and 6 plus?

So we know that the new iphones 6s and 6s plus will get the new live photos feature, but do the old iphones like the 6 and 6plus also get this feature?