I want to upload my first game on itch.io so that people can try out my game and give me feedback on how is it. While it is short (since it's created in a month for a project by myself), I want to show it off and see what people think of it. Here is a few question I would like to ask:

1. This game is written in Python using Pygame. Is there a way for me to make it playable only on browser?

2. While the code, drawing, and sounds are free software and created on my own, I did use copyrighted music for my game. As long as I don't sell this game, would it be okay to upload it?

3.Is there other requirement/condition before and after I upload my game?

Thank you for your time reading and answering my questions.

I'm not the best person to answer your questions, but here are some starters:

1. While there's at least one Python interpreter for web browsers (named Brython), the PyGame API is another story entirely. You'll have to rewrite your game for the various HTML5 APIs instead. As that can take time, maybe look at a framework like Phaser first?
2. Unless you have a license to the music, either implicit (free culture) or granted by the rights holder, using it in your own game is copyright infringement, regardless of price. But that's your problem; to the best of my knowledge, itch.io doesn't police its members in that regard.
3. There are some submission quality guidelines you'll want to review before uploading your game, but they're easy to meet and likewise not heavily enforced. Mostly it's just common sense stuff to get your game noticed at all (let alone well-received). Don't worry too much about it.

Hope this helps!

These are all really helpful information. Thank you so much!