Other Items are merchandise you can sell as part of an event. This can include fees for add-ons such as meals or childcare, raffle tickets, and swag items (tote bags, t-shirts, etc.). Configuring items to sell during an event is an optional step (this is not required).
By default, any items on your Default Event Other Items list (Configurations: Events: Other Items) will auto-populate to every new event you create. If you don't wish a default other item to be listed on the event registration screen as available for purchase, you will need to delete the item(s) from the event. Only items that are available at a majority of your events should be added to the default list. Otherwise, you can simple add "one off" items (that are specific to a particular event).
To get started, open/view your event and from the left hand menu select Other Items.
In the resulting screen you will see a list of all currently configured Other Items for the event (this will include any auto-populating default Other Items and any items that have been manually added to this event).
You can Edit or Delete any items by clicking the drop down to the right of the item name.
To create a new Other Item option for this event click on the Add button in the lower right of the screen.