Ho boi, that.. hooooo. That one took me awhile to grasp and I’m not sure I have the solid understanding needed to convey it. Something about sometimes light acts as a wave, sometimes it acts like a particle? I’ve heard someone else say “photons” are used as more of an illustration tool, because when you get down to it, light is weirder and freakier than a mimosa-laden aunt.
The super over simplified version is all matter is essential very compressed energy. And the whole matter vs energy spectrum is more of a continuum than a hard line. Photons are pretty close to the middle of the continuum, it is useful to use photons for some math, and waves for other math, but they're both equally valid.
Photons are a type of particle known as a boson, and are considered an elementary particle of the universe like quarks are. While bosons may have some properties that are similar to matter, they are not entirely identical.