If you're a service provider, consultant or external technical authority getting certificates on behalf of third party organisations, CertSimple's excellent for you. Your client will need to be aware of the process, and confirm you have permission to get and manage HTTPS certificates on their behalf.
For incorporated companies, we'll contact the address as published in a Qualified Independent Information Source - ie, a suitable business directory. The contact details here must be for the customer themselves. We'll automatically take care of finding this if it exists and assisting you in creating it if it doesn't. The customer should be expecting the call, and aware that you're requesting a certificate on their behalf.
As a consultant, enter your own email address as technical authority - we have a number of customers who manage certificates on behalf of their clients this way. You can log in, see all certificates for your clients in one place, sorted by the legal name of each certificate.
You or your customers can pay for the verification / cert - it's up to you. Billing and verification are completely separate and we won't look for the name used in verification when billing the card.