To buy an OV SSL certificate, you must provide proof of the organization's legal existence, verify that the organization controls the secured domain, and provide the required contact information. The certificate authority will typically require business registration documents, proof of domain ownership, and contact information for the organization. OV certificates are a higher level of validation than DV certificates, which only require evidence of domain ownership. OV certificates are typically more expensive than DV certificates but provide a higher level of authentication and trust for website visitors.