The Event timezone is what defines the date and time of the Emails and Notifications, the time of the Sessions as well as the data available in Analytics reports. For the latter, if the Organizer changes the Event timezone after users performed some actions tracked by the platform, the time of these actions will be displayed in the reports in the previous Event timezone.
Therefore, ideally, you will want to define the timezone of your Event right when you start building it and avoid changing it once the Event is "live".
If you run a Virtual Event, it's important to know that, by default, the times displayed for each user will be adapted to the timezone set on their own device (at the device level, not within Swapcard). That is not the case for Hybrid and Physical Events – by default, times will be displayed in the Event timezone.
It is therefore important that you select the correct type of Event between Virtual, Hybrid, and Physical. This can be reviewed, and if required, changed under Event builder → General information → Format