To help coordinate and navigate to various parts of your website, subdomains serve as an extension of your domain name. You may also use a subdomain to send visitors, such as your social media page, to a completely different web address or point to a particular IP address or directory within your account.
Take store.yoursite.com, for example. In this example, the subdomain is shop, the primary domain is your web, and the top-level domain (TLD) is .com. As your subdomain, use any text, but make sure it's easy to type and remember.
The most common use of a subdomain is to create a version of a website for testing or staging. New plugins and updates on a subdomain staging platform are also checked by developers before releasing them live on the Internet. Subdomains are also perfect for mobile sites (m.yoursite.com), location-specific sites (uk.yoursite.com) and sub-sections of the web (blog.yoursite.com) to be categorised and isolated.
Another popular use of a subdomain, like our example above for shop.yoursite.com, is to create an online eCommerce store. Having your store on a different subdomain helps to make purchases easier to manage, as eCommerce sites generally need a more complicated setup.
It is possible to create subdomains as an A record which points to an IP address. Or they can be created as a CNAME pointing to a different domain name. An IP address can never be referred to by a CNAME.
It is possible for each domain name to have up to 500 subdomains. Multiple subdomain levels, such as info.blog.yoursite.com, can also be added. A subdomain can be up to 255 characters long, but each level can only be 63 characters long if you have several levels in your subdomain.