Multiplayer Wont Save?

When me and my friend play multiplayer and we end the game session, my progress saves for me in my world but it wont save for my friend and here world and edits she made while in the session it just brings her back to a specific point when we started the game. Is there any way to fix this problem?

 

This is because when your friend joins you, you're not both going into some new universe, she just comes over into your own universe. If she wants to progress in her own save file, you need to join her instead.