Because of I made my house from the unity editor I can't remove this mesh borders. I tried MeshCombiner but it just connects all of the meshes in one mesh borders still exist. I know I can make it from Blender or something like this but is there any one to remove from unity?
Screen Shot: https://i.stack.imgur.com/dbWJN.jpg
Maybe you are looking for CombineMeshes. An example is