You can create a new item using one of your existing items as a template. Id doesn't matter if the existing item is in your user workarea, the review workarea, or in the live archive.
To do this, go to "Manage deposits" and open the item you want to use as a template by clicking on the icon "View Item". You get to the details page of the item where you can select the "Actions" tab.
Here you find the button "Use as Template".
Pushing the button will create a new item. This is a copy of the existing item, thus, all the metadata is already filled in and can be edited now. There is no link between both items, they are completely independent from each other.
Tip: You can create an item in your user workarea where you fill in the fields where you often need the same values, and use this as a template for other items.