To copy an item inside the same project or folder, select the item and then click the copy icon in the menu. After the copy icon is selected, the paste icon will be activated. Click the paste icon and the copied item will appear at the top of the list in edit mode. You may edit the newly copied item and then click save. The copied item will be added to the end of the active list.
In the Requirements and Plans app you may copy or cut an item and paste it to a specific location. Simply select the item, click the copy or cut icon, then select the location to paste it. The item is pasted above the item selected.