For more, see Draw Tools, Line Features
To activate: (in Edit Layer mode) Toolbar
Draw line features such as road centerlines, water lines, and streams.
To use:
Activate Draw Line tool.
Click on map view at desired beginning location.
Move pointer and click at each desired break / corner / vertex.
Right-click and select End Feature to finish.
To undo the last drawn vertex while drawing a line feature, right click and select Undo Vertex.