How are hydrogen bonds related to polarity?

Polarity affects hydrogen bonding because hydrogen bonding occurs due to a bond being polar. One side of the bond will be slightly more negative because it's pulling more electrons towards itself and the other side of the bond will be more positive. Therefore the partially positive bond of one molecule will be attracted to the partially negative bond of another molecule. This is called an intermolecular force and hydrogen bonds are the strongest intermolecular force.