What are the mechanisms of polarization of dielectrics?

In an electric field, the dielectric is polarized, i.e. displacement in opposite directions of dissimilar charges that make up the atoms and molecules of matter. So The nearest surface of the dielectric acquires a charge whose sign is opposite to the sign of the charged body. On the surface of the dielectric, bound charges appear, which are unable to freely move along the dielectric, in contrast to free charges in conductors.
The physical quantity equal to the ratio of the modulus of strength Eo of a uniform electric field in vacuum to the modulus of strength E of the electric field in a uniform dielectric filling this field is called the dielectric constant of the substance: e = E0 / E.