Registration is the process of getting the member's information recorded. This can be done at the time of membership sale, or when the member physically arrives at the convention. The amount of information to be recorded is highly variable, from nothing, to just name and address, to all the particulars of interests and activities the member intends to engage in at the convention. The intended use of the data will determine what is requested of the member.
The Registration department manages both Pre-Registration and At-Con registration. Some conventions have separate people in charge of the two functions. Pre-Registration is done by mail, in person at Room Parties and other events, and online. Whenever pre-registrations are taken in person, a receipt should be given to the registrant as proof of their membership.
There is usually a Registration Desk at the convention, though Program Participant Registration may be handled through the green room or simply filed separately to support the handing out of program participant information packets. If you do separate out program participant registrations (or any other category of member), it's important that the people be told in advance where they should go to pick it up, and that that place be open at least all the hours that registration is. Nothing makes program participants think you're disorganized or incompetent faster than not being able to get their registration!
Registration is one of the bigger responsibilities and jobs in a convention. In addition to handling the vast majority of the convention's money and interacting with every single member, registration also is responsible for capturing contact information from each member that will enable the con's publicity activities in the coming year (sending progress reports for the next convention to the people who attended this or a recent one). Usually, Registration also assumes ownership of the information in question, and responsibility for it accuracy, between when it is collected and when it is used.
Registration may also be responsible for badge production; at the minimum, they need to provide the information (at an absolute minimum a count; often these days the information to put on pre-printed badges) needed for badge production.
Some conventions prepare "registration packets" for each member, containing their badge and anything else to be handed to each member. This can be handy, since it provides a place to put special things to be given to an individual member, like notes, program participant information, and the like. On the other hand, they take a lot of work to prepare, and things like the program book are more easily simply kept in a pile on the desk and handed out. Program participants can go to the green room or program operations to get their program information.
Some conventions include memberships with Dealers registration or allow Programming to give free memberships to program participants. If these processes do not require the attendees in question to contact Registration themselves, be sure that you have a way to get their information.
At-con registration should be physically located in the most obvious location possible.