If you want to create a subdomain, you will need to login to your cPanel. To access your cPanel account, please visit www.yourdomainname.com/cpanel (replace 'yourdomainname.com' with your actual domain name) and login.
Once inside your cPanel account, you can create a subdomain by completing the following steps:
1. Click the 'Subdomains' icon under the 'Domains' section.
2. On the next page, enter the prefix you want to use for your subdomain. For example, if you want your subdomain to be support.yourdomain.com, then you should enter 'support' in the 'Subdomain' field.
3. If you enter a valid prefix in the 'Subdomain' field, the 'Document Root' box will automatically update. Click the 'Create' button.