Login to your cPanel

There is an icon “Subdomains” within the area of “Domains” in your cPanel, click on it to proceed

In the field “Subdomain” enter the name of your desired subdomain for example “blog” and select the parent domain from the dropdown next to the field “Subdomains”. It will then become blog.yourdomain.com as a subdomain.

Now just click in the field “Document Root” and your click will automatically fill the field with the suggested location.  In the case of blog, it will be automatically filled with the document root “public_html/blog”

Now simply click “Create” to complete the process of setting a subdomain.

Note: You can manage or delete the already configured subdomains from the area under “Modify a Subdomain” search box, where the already configured domains are listed.