Match Topology works in conjunction with Create Deformers > Blend Shape. Ordinarily, you do not need to run Match Topology, because the Blend Shape operation does it automatically.

Match Topology prepares multiple subdivision surfaces to be blended, such as copies of a character’s head in different poses. In order to blend subdivision surfaces, the surfaces must have the same vertices at all levels. Match Topology adds vertices as needed to make the vertices match on all selected objects.

You do not need to do Match Topology yourself, because the Create Blend Shape operation does it automatically. Do it only if you want to see the results before the blend shape operation. Note, however, that doing Match Topology yourself will lead to slower system performance when you blend shapes.

If you do Match Topology, first select two or more surfaces in any order. The surfaces must have the same number of faces on level 0. They do not necessarily need to have the same number of levels.

Match Topology only adds vertices. It does not match the vertex position edits or creases from one surface to another.