High assurance certificates include your domain name as well as business registration details on the certificate. The certificate authority will verify your ownership of the domain name and business registration (you will be asked to submit a few documents).It can take a few hours to a few days for a high assurance certificate to be issued depending on when you submit the necessary documents.
Low assurance certificates include only your domain name in the certificate. Certificate authorities usually verify that you own the domain name by checking the WHOIS record. The certificate can be issued instantly and is cheaper but, as the name implies, these certificates provide less assurance to your customers.
