Step 1 Press Insert + F7 to get a list of links on the page. Search for the Edit Label link and press Tab to Move To Link then press Enter to get the focus on the Edit Label link.

Step 2 Press Enter again to get a dialog to add a label. JAWS will say Add Label Type in text. Then type in the label you want and press Shift + Enter to  Add the label. 

Step 3 Once you have add the label press Tab to access a set of labels for the page.

Step 4 Press Escape to exit the Add Label dialog box.

Note: Pressing Insert + 3 and then pressing l will bring the Add Label dialog mentioned in Step 2.