So, sometimes people who go to church want to become a member of that church. And when they do, the leaders of the church might give them something called the "right hand of fellowship."
Now, this doesn't mean that they're actually giving them a hand. It's more like a special kind of handshake - kind of like a secret handshake between church members.
Giving someone the right hand of fellowship is kind of like saying "we welcome you to our church family" or "we're happy to have you here with us."
It's a way for the church to show that they're happy to have new members and that they're willing to support them in their journey of faith.