I need to join a vertex to edge, with *snap to edge* i can snap my vertex on the edge but i don't know how to join it.

Now my solution is:

1. snap vertex to edge
2. subdivide edge (this creates a new vertex on the edge)
3. merge the two vertices

But i think is too elaborate, so i look for a simpler solution.

[![enter image description here](https://i.stack.imgur.com/iwxC8.jpg)](https://i.stack.imgur.com/iwxC8.jpg)
['https://blender.stackexchange.com/questions/94754', 'https://blender.stackexchange.com', 'https://blender.stackexchange.com/users/48600/']
Subdivide is a bad option in your situation because you get more verticals than you need.

The fastest way, in my opinion, is to manage this with a loop cut.

1. Loop Cut `CTRL`+`R` and slide to the position where you want to connect your vertex
2. Select your vertices and merge `ALT`+`M` them

[![enter image description here](https://i.stack.imgur.com/vGrqD.gif)](https://i.stack.imgur.com/vGrqD.gif) 

You could the same with the knife tool (`K`). However you can't guarantee for a good mesh flow if you do so. 
With Loop Cuts you are most of the time on the good side.
If i understood the question maybe a quick solution.

Download the [addon Snap utilities](https://github.com/Mano-Wii/Addon-Snap-Utilities-Line/blob/master/mesh_snap_utilities_line.py) 

Press `T` in toolshelf -> Snap utilities ->

Select the single verts and click on the line from the addon and draw the line from verts to edge. You will get a edge and a new verts.

To confirm the operation press `Enter` To Exit `Esc`

[![enter image description here](https://i.stack.imgur.com/AIyN1.gif)](https://i.stack.imgur.com/AIyN1.gif)