Once you have successfully created a new user, you will be taken to the Admin User Account page for the new user. In this area you can see what their event and area accesses are and also view their account 'state'. A new user's state will be shown as 'pending' until they activate their account - the account becomes active once the user has selected the link contained in the activation email they received upon creation and they have successfully logged into the application. Following this, the user's account 'state' will change to 'active'.
Users that have not activated their account will be shown as 'pending' on their account state when viewed within an event, but when viewing their account in the Admin Area you have the ability to resend their activation email to ensure that they have received it. To do this, just click on the button at the bottom of the page and a new activation email will be sent.
You can sort users in either your event or Admin Area 'Users' index by their current account state - selecting this option will group all users at the property as 'pending' or 'active' depending on their activation status.