Electromagnetic fields describe one of the four fundamental forces of nature.
They are created by a flow of electrically charged objects or an electrical current.
The electromagnetic field could be seen as an electrical field, created by any charged object and a magnetic field that is created by the movement of charged objects.
Electromagnetic fields affect all charged objects in the vicinity of the field.
These fields' span is limitless.
That is, there is no detectable point where charged objects are no longer affected.
Electromagnetic fields affect matter by transferring energy from the electrical current out to all other matter.
Electromagnetic fields according to quantum mechanics are regarded as a physical field of photons.
Photons or elementary particles are what make up all of forms of light and are not created from smaller particles.
These photons could be seen as carrying the energy away with a certain frequency.
Matter can absorb the photons and the matter will receive the energy and momentum through the photons frequency.
I will not be discussing the classical perspective, as I don't find it useful.
Charged objects are so because of the balance of protons and electrons within the atom.
An atom is a nucleus of protons and neutrons with a shell or shells some distance away that hold electrons.
You might say these electrons are fickle.
They bounce around always looking for a stable place to land rarely finding it.
Atoms seek to be stable.
A stable atom has the full capacity for electrons in its outer shell.
Very few atoms have this.
An atom is electrically charged when the number of positively charged protons and negatively charged electrons are unequal.
When you rub our socks on the carpet electrons are jumping on to you giving you a charge so that when you touch something that a charge will move through easily i.
e.
something conductive like a doorknob you can feel the charge jump from you to the metal as a shock.
This is happening constantly.
Most objects are charged one way or the other.