A certificate of the type "Wildcard" offers many advantages at a favorable price. Such a certificate covers not only the root domain, e.g. https://MyDomain.com, but also all subdomains below it, e.g. https://www.MyDomain.com or https://xyz.MyDomain.com.
With this solution you can easily protect and secure an unlimited number of subdomains. If you have any questions about this, our sales staff will be happy to advise you.