There are two ways that you can add extra label sheets in Microsoft Word.
1. Is to use the Mail Merge feature instead. You will then need to add all your recipients into a list (e.g. in Excel). Then you just import those addresses into any label layout. This is also the preferred way in creating label sheets in Word when there are pages of pages of addresses.
2. You can simply add an extra table row into the end of the sheet. Since the label sheet layout is just a modified table with preset heights and widths, by adding an extra row you can accomplish the same result. The only problem we noticed is that sometimes you will need to re-adjust the layout a little on those extra pages.