It is an electrostatic force of attraction b/w a covalently bonded hydrogen atoms on one molecule and highly electronegative element (F,O,N, sp-hybridized C) of other molecule.
They are of two types . intermolecular and intermolecular
Intermolecular- H²O, HF etc
Intramolecular- O-Nitrophenol,O-Florophenol , Salicylaldehyde etc
It's stronger than Van der waal's force