What is stereoisomerism? Which are its types?

(N/A) Stereoisomerism is a form of isomerism in which molecules have the same molecular formula and sequence of bonded atoms (constitution),but differ in the three-dimensional orientations of their atoms in space.
Stereoisomerism is primarily classified into two types:
$(i)$ Geometrical isomerism (also known as cis-trans isomerism).
$(ii)$ Optical isomerism (related to the ability of a molecule to rotate plane-polarized light).