4 Different HTML from single Craft 3 CMS on 4 different domains? Can we serve 4 different HTML from single Craft 3 CMS on 4 different domains?

working on a client project which has their 4 different domains for their different brands of the same business. 

Is it possible, if yes how can we achieve it?

Thanks in Advance ..!!
Yes, you can. How you organize the templates for each site is completely up to you. Here's the docs on setting up multiple sites in Craft.

I would likely use a different layout template for each site. So when I extended at the top of an individual page template it would look like this.

{% extends "layouts/_site_one" %}


Or like this

{% extends "layouts/_site_two" %}