Electromagnetic interaction is a fundamental force of nature and is felt by charged leptons and quarks. Its exchange particle is the photon (symbol γ) and the many forms of electromagnetic radiation are a manifestation of this interaction.
Rutherford scattering showed that the electromagnetic field has a greater range than the weak or strong fields due to the photons having no mass, and travelling at the speed of light. The fact that photons have no mass makes them easy to produce, and charged particles usually interact electromagnetically before other fields have a chance to operate.
Electromagnetic interactions are long range attractions or repulsions between any particles or antiparticles that have charge. If the particles are attracted they stay together, because there is a continual exchange of photons.