Should I choose SAN or Wildcard certificate?

Wildcard certificates are issued for a single root name (eg *.mydomain.com) and can be used for unlimited subdomains, based on the root. Thus, in addition to the main domain, it can also be used to protect unlimited subdomains of the format: ftp.mydomain.com, blog.mydomain.com, mail.mydomain.com, etc.

SAN certificates protect multiple unique Fully Qualified Domain Names (FQDN) with different root names. You can, for example, protect mydomain.com, mydomain.gr, newdomain.net with the same SAN SSL.

Depending on the services you wish to protect, you make the corresponding selection.