Every face has a normal. Every vertex also has Normals and probably even edges has Normals. Their length I think only matters when it comes to baking most likely. But you don’t have to worry about any of that right now, it’s only the Blender Basics and Normals are a very technical and kind of advance topic. So for the moment I think the most important thing to know is that the front of the face is where the normal is pointing, and the opposite is the back of the face, this matters because is how Blender will know what to do with the surface of your object.
