View this tutorial video to learn how to add a subdomain to your account:  
How to Add a Subdomain | Creating a 2nd Domain | Updated Oct 6,2021

Reason:
The main reason is to give your webpage a separate identity in search results, while keeping it as part of your main website.
Example: dataczar.com is our main website.  We have connect.dataczar.com as our website builder/hosting site.  We also have help.dataczar.com as our help site.

Steps:
1. Create a website
> Go to the Website button on the Main Menu > then click on the (+dropdown)
> Select Create New Website > and add your website name
          For example: we'll use: blog.hikelesstraveled (as our website name)
> Click Create

2.  Create your subdomain and select hosting
> Go to the Domains button on the Main Menu
> Click on Settings (blue gear button)
> Click on Advanced
> Click on Hosting
> Click on Add Subdomain
> Add your subdomain name > click the dropdown and select hosting 
          For example: we'll select blog.hikelesstraveled.com
> Click +Add Subdomain

3. Now go back to the Website button to view/edit your subdomain website!