Add Vertex

For more, see Draw Tools, Vertices

To activate: (in Edit Layer mode) Toolbar

Place additional vertices along the length of a line or polygon feature.

To Use:  

1. Select feature to which vertex / vertices are to be added.  

2. Activate Add Vertex tool.

3.  Move pointer to desired location on feature and click to add vertex.

4. Repeat click as desired for additional vertices.

Note: When adding a vertex to a line common to 2 selected polygons a vertex is created in the same location for each polygon.  (Helpful when splitting polygons!)