Comodo (now Sectigo CA) does not require any other verification procedures for PositiveSSL Certificates, other than validation of your domain ownership. It can be done by either receiving the validation email or uploading a certain text file into a particular directory of your website (/.well-known/pki-validation/) or adding a certain CNAME record to the DNS zone of your domain.
NB: If you have activated the certificate with domain.com or www.domain.com indicated as FQDN in your CSR code, please make sure that the file is available via http://domain.com/.well-known/pki-validation/file.txt . In this case, www.domain.com is considered to be under your control as well
