Similar to the property labels, electrical wires that participate in schematic connectivity can have a bound label that provides a name for the net containing the wire.
Unlike the device labels, wire net labels are created by the user. If the label command is started with a single selected wire on an electrically-active layer, the label created will be bound to that wire. Thus, to create a label for a wire, select the wire, press the label button in the side menu, and create the label. These labels can exist on any layer.
Once created, these labels can be edited in the same manner as property labels, i.e., select the label and enter the label command by pressing the side menu label button.