By default your event invoices and confirmations will be emailed using your name and email address.
If you have multiple users (see features) you can configure different contacts to be used for each event.
You add additional users via the Settings -> Users menu:
Clicking the “Add User” button displays the user form:
For the user to be selectable as a contact for the event the “Show in Contacts List” needs to be switched to “Yes”.
If the user being added is to be an event contact only and does not require to log into the Event Gate administration site, just add them as a “Contact Only” for the Role:
Now, when you edit your events, your new event contact is selectable from the Event Details tab: