Yes, it is possible to use an SSL certificate on multiple subdomains, depending on the type of SSL certificate you have.
Wildcard SSL certificates can secure a main domain and all its subdomains with a single certificate. For example, if you have a wildcard certificate for "*.example.com," it will secure "www.example.com," "blog.example.com," "shop.example.com," and any other subdomains.
However, it's important to note that not all SSL certificates support multiple domains or subdomains. Be sure to check the certificate specifications and consult with the SSL certificate provider to ensure compatibility and the ability to cover your specific domain and subdomain needs.