Before you go posting your music online, there are a few things you are well advised to heed so you have no regrets. The experts tell you to not only copyright all your music, but also get yourself listed as the music publisher, because the more hats you wear, the more money you will get from the slice of the pie.
I highly recommend the following 2 books, that can help you dramatically and save your a lot of heartache:
I have this book on Music Publishing
which is for the American audience. I believe it is also used in colleges. Read the reviews and you'll see why it gets good marks. 408 pages, and it's good reading.
This book is also highly recommended, and more on point with your original idea regarding posting your music online:
Social Media Promotion For Musicians - 3rd edition
It's too much to write, but this guy Bobby Owsinski, has been in the business for decades and is probably most well-known for his book "The Recording Engineer's Handbook", and "The Mixing Engineer's Handbook". He hosts live conferences with Users and students and music reps allowing us to ask questions and get answers from the people who know, and goes to big music affairs as a guest speaker, and more. I saw him at Sweetwater
Music Summer Gear Fest 3 years ago.
Self promotion and how it works today to get yourself known is nothing at all like the music industry worked 30+ years ago.
In this book, it lists the things that get asked a lot and goes into detail so you don't make mistakes, and the book is updated. He has interviewed countless people in the industry and brings the answers to the public assembled in an orderly way to spare you lots of heartache.
Click the link on his website for the 3rd edition published April 5, 2020 and it will bring you to Amazon to buy. Also read the comments on Amazon. You'll be impressed with this book, too. It's a lot easier reading than the legal "Music Publishing" book I first gave link to. You'll probably want both, though.