Blender 2 8 Add Vertex
One of the above or use knife tool.
Blender 2 8 add vertex. If you want more than one vertex use subdivide multi. Initially the group is named group or group nnn when the name already exists and gets displayed in the panel 2 see next image. You create a vertex group by lmb on the add button on the right panel border 3. You can add a single vertex as a new object using the extra objects method.
To create interconnected vertices you can add a vertex and continuously make subsequent ctrl lmb operations. Select the edge you want to add a vertex to and press w subdivide. Because the camera space computer screen is two dimensional blender cannot determine all three vertex coordinates from a single mouse click so the new vertex is placed at the depth of the 3d cursor. Edit mode select vertex press e to extrude only vertex.
Blender is free and open source software download. To do this navigate to the edit menu and hit preferences. Blender 2 8 comes with this add on readily available but you ll need to activate it.