I wanna make a website to allow users to download audio files . Where can i store those audio file. I read about amazon s3 . What is it and how to use it to store my files ? How to serve those files to the website ? Should the website be hosted on amazon too ?
There is no need to have your website hosted on Amazon.
You can use S3 to store your audio files and then use the public links such as
https://s3.amazonaws.com/bucketname/audiofilename inside your website to point to those static files.