How to Publish our websites??

you can do it for free if you use github. I have hosted many if my sites through github you can check my github profile the link is in my profile

Bro read this https://www.google.com/amp/s/www.hostinger.com/tutorials/website/how-to-upload-your-website/amp/

You can use pythonanywhere API with github and upload your existing project for free

For that, you need to buy a domain. There are many companies that are willing to host your website on their server for a price.