When you have a standard civil ceremony at city hall you are required to check-in at the Clerk's office 10 minutes before. The purpose of the check-in is to show the county clerk that you have the correct documentation. This includes having current Identification and also a Marriage License. Once you check-in they provide you with a ceremony number. This is what the couple is displaying in the image above. Once they call your number, you go back in to the Clerk's Office and meet with the Officiant of your wedding to discuss what will take place. It is also nice to get a chance to meet each other and develop rapport prior to the ceremony.