First, make sure you have the FINAL host name that you are securing. www.somehost.com and somehost.com are equivalent, but www2.somehost.com and somehost.com are NOT. For an EV cert you will need to do this once for every host you wish to get a cert for. For this reason you cannot get a wildcard EV cert.
If your business entity has a data trail (think info-usa type stuff) then you are probably golden. Otherwise you need:
A Requestor (probably you)
A Request Approver (someone at the company that can be verified)
An Approver (someone at the compnay that can be verified)
They can all be the same person and many times will be.
The CA will need your business registration #, city, and state. (your HQ address might be different than this, they need the info where you registered)
If the CA cannot find enough information in public records to validate your contacts, you will need to have their accountant (CPA) send a letter stating they represent the company and its contact info (mailing and telephone) along with contact info for the person who will be your Request Approver/Approver. Make sure all the addresses match up. This letter could also come from legal counsel who is registered with the state Bar association of the state your company is incorporated in.
In general if you make a typo in anything but the certificate request info, the CA can correct it after you initially request.
