I cant join my friends server on minecraft

So im trying to join this server that my friends have created and its not letting me join and im not sure if its because im on an ipad and my friends are playing on their computers. I would like to be able to join the server and play with them. Multiplayer
doesnt work if my friends are playing on their computers like if their playing minecraft on their computer and im playing on my ipad i then can not join them. Please let me know how i can fix this. Thank you

:)