The validation process depends on the type of SSL certificate. The first validation for all these types will be domain ownership verification via approval email or an alternative validation method.

Please keep in mind that every domain within the certificate should be validated. Thus, depending on the number of domains, ownership verification may involve several approval emails.

The Organization Validated and Extended Validated types will most likely require you to submit documents to the Certificate Authority for verification.

Please check the detailed information about the validation requirements for each of the types via the links below:

Domain Validated certificates

Organization Validated certificates

Certificates with Extended Validation

You can find even more articles regarding the validation-related topics in this category.