how to add vertex to mesh?

Hello - I am brand new in the world of Blender.

I study architecture.

Can any one help me on the subject of adding vertex to a mesh. Not by subdividing, but free - just where I want them. For the purpose of extruding smaller parts of a mesh.

Thanks a million!

Best, Astrid!

Well, you can select a vertex, an edge or a face, press ‘E’ and move the extruded vert, edge or face wherever you want.

You can select any one of the vertex then press ctrl + LMB will create new vertex or use E key to extrude the vertex.

ctrl + LMB is a nice tool, it creates vertices on a plane perpendicular to your current view, the depth of which is determined by the 3d cursor.
If you have nothing selected, a floating vertex will be created, otherwise it will extrude your current selection. Very good for sketching.
A good tool if you want to do some exact stuff is also the shift+s menu where you can snap things to certain positions, for example the current grid level in ortographic side/top/front view.