You may occasionally need to duplicate a field, such as when you need to implement multiple, more complex, fields. A good example would be if you've created a complex formula that draws information from various other fields or collections. You want to copy that formula, but just change one or two of the inputs. Instead of writing it all out again in a new formula field, you can just copy the original field and change the relevant parts. Duplicating a field will copy the existing field's properties, and you can optionally copy the values of the fields, too.
To duplicate a field, click on the field name from an expanded item. Click "Duplicate". To copy the field values, turn the toggle in the confirmation dialog to "On". The duplicated field will appear at the end of the list of fields in each item.