I'm using Navicat 11, have a feeling this might not have been so easy (or even possible) in some earlier versions. To do this in Navicat 11, access the table you want to duplicate a record in, so that you can see the rows of data. Right-click the small shaded rectangle at the head of the row you want to copy, left-click 'Copy' in the pop-up menu. Click the '+' that you see at the bottom of the window. Right-click in the left-most field of the new, empty row and left-click 'Paste'. If your new record breaks a Unique key rule, as it usually will, simply amend the newly-created record e.g. by clicking in the field for the auto-incrementing key and editing it to have the next available value.
Edit: this is apparently possible in Navicat version 7 and later