The Record Source column indicates how each guest was added to the Guest List. This column can be found in the Guest List Summary report, Confirmed Guests report, and Unconfirmed Guests report. The Record Sources are as follows:
API Addition: Guest was added using Check-In.
Direct Invite: Guest was added through Guest List > Invite/Add Guest.
Import: Guest was added or invited through an uploaded list.
Transferred: Guest was added when a ticket was transferred to them by another guest.
Public Interface: Guest registered for a public purchase or public registration ticket using the Public Site.