You can create dynamic action to clear items in Oracle Apex. Follow these steps:
Creating Dynamic Action to Clear Items
In the below example, I am creating dynamic action on a button for the click event to clear items.
Do right-click on the button, then select Create Dynamic Action from the shortcut menu.
It will create a True action by default, click on it and change it to Clear from the drop-down menu.
Choose selection type Item(s) and specify the items to clear. Below is the screenshot: