Covalent bond

Covalent bond is a form of chemical bonding that is characterized by sharing electrons between atoms.
Depending upon the number of shared electron pairs there are three types of covalent bonds - single, double and triple.

Covalent bond can polar covalent bond and non-polar covalent bond.
Covalent bond is said to be polar when the shared electrons move toward the atom with greater mass whereas in non-polar covalent bond, the shared electron pairs are at equal distance from  both the atoms involved in bonding.

Example of non- polar covalent bond is Chlorine molecule and that of polar covalent bond is HCl