The DV certificate (domain validation): This is the easiest to validate. To obtain this certificate, simply justify that you are the owner of your domain name. A simple file at the root of the site or the validation of an e-mail of the domain is enough. No certification authority has verified the identity of the site owner. Anyone can get this type of certificate.
The OV certificate (organization validation): The OV SSL certificate is a little more complex to obtain since you will have to prove that your company or organization really exists by producing supporting documents. This is, for example, the certificate used by Wikipedia. The certifying authority verifies the legal existence on the basis of official documents.
The EV certificate (extended validation) : The EV SSL certificate is probably the must. If the validation is more complex, because even the identity of the manager of the organization must be validated (in addition to everything else), this certificate has the advantage of displaying the name of the company in green in the bar browser address in addition to the green padlock. This certificate is the one that will eventually reassure the best users when they have become used to it. Given the differences in rates with OV certificates, EVs are a good choice even if they are more complicated to validate.