If you own a domain name and ready to register another one, so you can register the new domain as a sub domain to your main domain. It will be available for free of cost but has it’s limits based on the hosting plan you have chosen.

Step 1- Login to cPanel.

Step 2- Click Sub Domains under Domain section.

Step 3- Follow these steps below.
1. Type your new Sub domain name in the text box named as “sub domain”.
2. Choose your main domain which you want to register the sub-domain.
3. Document root will generate automatically.
4. Click the Create button and wait.

Step 4-  Now you have a new sub-domain under a main domain.

Done!