There are a great variety of certificates.
Let’s sort certificates by two attributes. They are “Object” and “Validation level”.
Object includes single domain (such certificates protect one domain and subdomain with www), multi-domain that includes many different domains under one organization name and sometimes even subdomains could be included.
Third type is a wildcard, that can protect a lot of subdomains of single domain. Depending on seriousness of validation status there are DV, OV and EV certificates. Depending on purpose of usage most cheap and quick is domain validation method. It validates only domain ownership.
Legal companies prefer organization validation (this more expensive variant with organization name shown in certificate details) and EV (EV certificate also showing organization name to the left near address bar).
Detailed description of DV / EV and OV and their differences is available in our additional article.