I can't find people that join me on Minecraft Pocket Edition?

I have the Apple iOS version the main edition not the lite. I'm not new to mine craft I've played for many years but whenever i play with a friend that sits next to me and joins my world they can't find me or i can't find them. Is there any way i could teleport them to me or someway to find them easily? I've looked everywhere online but there's no one that has this issue apparently.