In addition to receiving email when you're invited to become a member of a company/organization's team, you can access these invitations inside your user profile.
Access your invitations:
1. Click your user name/avatar at the top right of the page.
2. Select User Profile.
3a. Click Accept.
Note: If you are a member of another company in EventCollab, you'll receive a pop-up notification that you'll be removed from events you're currently associated with, so consider carefully which company and events have priority.
3b. Click Cancel in the notification pop-up, then click Decline, and you'll be taken back to the My Information tab.