Is microwave a form of electromagnetic radiation ?

Put simply, yes. And it is the smallest frequency of the electromagnetic spectrum. Here is a link to a Wikipedia page. https://en.m.wikipedia.org/wiki/Microwave

Hope i helped, even if i didn't, I hope you have an excellent day.
Love, Maddie <3 .

Microwaves and visible light are both electromagnetic waves. The difference is in their wavelengths. Microwaves wavelengths range from 1m to 1mm (corresponding to frequencies of 300MHz to 300GHz) and light waves wavelengths range from 390nm to 700nm (frequencies from 430 to 790 THz; 1THz = 1000000MHz).

yes