How to determine the document type by key points on a graphic image?

Question

Text recognising

Good day everyone.
I ask for your advice.
Tell me which way to look? The task is to determine the type of document by key points on the image, there is a set of typical documents, of which 3-4 are quite standard. Using the Opencv library, I define a certain set of points and lines. It is necessary to draw a conclusion about the type of document being analyzed by the coordinates (they may differ by small values) and the distances between them.
Perhaps there are standard algorithms / approaches to solving such problems.