In order to register for events and purchase store items you must have an account. This includes Delegates, other members and their guests.
Only members and delegates can register for an account directly and the membership details will be checked before the account is approved. This can be done most quickly if you have an account on the international website, mensa.org.
Once a member or delegate has create an account, verified their email and had it approved, they can add their guests, register and book events.