As far as i have understood it, Photons do not have Charge. Charge as i have understood it is the Positive and Negative charge of an atom.
In context to $\rm H_20$ being a polar molecule, microwaves ovens utilise the positive and negative polarity of the microwave to agitate the $\rm H_20$ Molecules creating kinetic energy and heat.
How is it so, that an EM Wave that has no charge, is able to agitate the charged particles of $\rm H_20$?