If you do not already have a Leap (formerly ShowClix account), you cannot create one before you buy your badges. A temporary account is created automatically when you place your order. You will receive an order confirmation email and a separate email notification with a link to finish setting up your Leap (formerly ShowClix) account.
The link provided will take you to the screen below to create your account:

If you see the below screen it means you already have an existing account in Leap (formerly ShowClix) and just need to log in:

Anime Expo has been using Leap (formerly ShowClix) for the past several years to sell both our badges and event tickets (concerts, Maid Cafe, Masquerade, etc.). If you purchased a badge or ticket in the past year, you should already have an existing account linked to your email address.
If you need assistance logging in, then please contact Leap Support by clicking on the "Need help signing in?" link at the bottom of the login screen or go to the Leap (formerly ShowClix) Event Help Center page to submit your support ticket.