Google Sites
Google Sites is a free to use website builder. It is very easy and intuitive to use, allowing users to easily create a website without the need of any coding knowledge. Users can easily use Sites to come up with a website for their project/showcase.
Google Sites support custom url as well, which is the focus of this site. To show you how you can use subdomains with Google Sites.
The limitations of Google Sites is that there is no support for advanced configurations, meaning you can't use Javascript on this site. Custom CSS is not allowed as well, and the styles are quite limited, you can try it out by looking at the themes page of your site, you can see that there is very limited number of themes for you to choose from. Of course, it being a Google product, means it integrates well with Drive, Maps and many more.
1.Go to settings
Click on the cogwheel
2.Enter your custom url
Ensure you see the checkmark symbol when entering your domain/subdomain
3.Save and publish
Once you see the url down there means the custom url will be applied to the site when it is published