Ensure that you have the inventory space for the item you want to dupe.
Locate the item you wish to duplicate in your inventory.
Press Ctrl + D to open the Debug menu.
In the Debug menu, click on the 'Dupe Item' option.
Input the item number or search for it if necessary.
Click on 'Dupe Item' to create a duplicate of the selected item in your inventory.
Once you have learned the steps, duping in Realm of the Mad God Exalt (Testing) can provide convenience and resources for your gameplay.