I would like to know how to connect with friends on Minecraft without everyone using the same WiFi Network?
You have plenty of options:
You and your friend can connect to same server. This one is probably the easiest solution, but you have to play with other people you dont know.
You can rent a server. Or you can use free online servers (active for 1 hour then you have to renew it etc. ). You and your friends can connect to the server you rented.
You can use hamachi (or similar application) to create a server. Your friends connect to your hamachi (or equivalent) and you create a local server. Your friends connect to game using multiplayer menu.
You can port forward and create a server. This is probably the hardest, and most performance-unfriendly solution, but stable. You can download minecraft server binaries, edit configuration for the server and start it. You and your friends can join it.
You can use a LAN cable to connect computers. Same as wireless technique, but with wires.
Besides these there is no way you and your friend can play together without being on same wifi network. (As I know)
Also a little research would give you results. Welcome to StackExchange.