Are there many ways to run a server?

I have few questions. I got into networking a few days ago, I'm still a big newbie, so please don't judge me.

1) To host a file, you need to have it on a localhost, am I right? Are there other ways?

2) I have seen python command for cmd: python3 -m http.server [port number] It puts the directory you are in into a localhost, right? Does XAMPP do something similar? Is that its purpose? If so, what does MySQL option do? I know it has to do something with databases, but I can't figure it out.

3) Except that python command (and maybe XAMPP aswell), I have heard that there are other ways to put something into a localhost. Is there a special way for Linux OS? Does Microsoft have its own way they have developed?

4) Most of the people on youtube use port 8000 for their server. Can you choose whatever port you want? Does port determine which protocol is used? If so, can I use port 80 for http?

Thank you in advance!!! Sorry for any grammatical mistakes, English is not my native language! :)