Just a little clarification here so that other people who may need this information don't get misleaded.

Foreign nationals who wish to marry a Turkish citizen in Turkey may only do so at a registry office and not at the embassy of their country. The marriage certificate given to the couple at the ceremony is an internation marriage certificate and is multilingual and therefore recognised internationally.

The Formula B form mentioned in this post is a multilingual record of the marriage. It is optional to obtain this document following a ceremony. It is issued by the local Office for Population Registry (not just the one in Ankara) and it may take up to a week for it to be ready. The registrar who marries you would be able to advise you where to go and how long it would take for it to be issued (it is sometimes possible to get this the same day). Although it is optional to take this document if you are a foreign national getting married in Turkey, I'd advise you to get this form when you get married and put it to one side as it is more difficult to get it later on.