There are three ways in which you can turn the visibility of joint labels in the scene view on and off:
Use the Display > Animation > Joint Labels or Skeleton > Joint Labelling > Toggle Selected Labels to toggle on and off the visibility of joint labels in the scene view for selected joints.
Set the visibility of a single joint’s label from the Attribute Editor. To toggle the display of a single joint’s label in the scene view, select the joint, open the Attribute Editor, and turn Draw Label in the Joint Labelling section on or off.