The Vertex is a place in the chart that is a point of intersection that seems to be sensitive to “fated” meetings with others. The opposite point is called the anti-vertex and acts like the Ascendant degree of self, were the Vertex acts more like the Descendent. degree of partnerships.
Generally a transiting conjunction from an outer planet to this point will bring on some type of fated meeting. Those who are drawn together for some reason may find that they have Natal planets in common with each others Vertex.
My husband has his Neptune, Venus and Mercury conjunct my Vertex, while I have my Moon conjunct his Vertex, and my Mercury conjunct his Anti-Vertex.
These meetings are more in line with teaching you something that you need at the time. The rest of your charts should also indicate this needed lesson. The Vertex brings this persons energy into your orbit so that you can learn or imitate them in some manner. This can be anything from learning to manage your finances to learning to interact with other folks in a different manner. In the end this is something that you have been missing as you grew up, a new way of “seeing” the world.
In some cases the lessons are quite pleasurable, in others more difficult, but in all, once this transit is over you will view the world through a new and hopefully better perspective.