Hey, I'm making a chat program so me and other students can chat in my high school and I've run into a problem

None of the computers are connect with any kind of sharing folder or network drive like i thought they were so I have no where for my program to store the chat files so I figured the only way to do was to pass the files online (all of the computers have internet) so can some one point me to the basics of file transfer online

I thank you in andvance :3