Is electron a matter?

Light (photons) doesn't have a mass. Particles that move slower than light have a property called rest mass. These particles can exist without moving around. But they still have energy given by Einstein's famous equation E=mc^2. Light waves with enough energy can crash into a sheet of lead and change into positive and negative charges with mass like electrons and positrons. By Einstein's equation light energy becomes mass. A useful way to think of energy and mass is that energy is water vapour and mass is drops of water. They are the same and different.

As Wikipedia says:

In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume.

Electrons are fermions, that is, elementary particles, that is, with no substructure.

A point particle is different from an elementary particle :

In quantum mechanics, the concept of a point particle is complicated by the Heisenberg uncertainty principle, because even an elementary particle, with no internal structure, occupies a nonzero volume.

Therefore, electrons have mass and volume, hence electrons are matter.