No, it is not. WiFi is composed of signals traveling by electromagnetic waves. These waves are the same kind of waves that make up the light that we see, except that our eyes were not built to "see" WiFi signals. We have structures in our eye which can only see red, green, and blue light. Red is at the bottom of the rainbow spectrum of colors that we can see (color corresponds to the wavelength, or frequency of light), and WiFi would be way, way below red. These waves contain energy, and in principle energy can be converted into matter and vice versa, but energy and matter are still different things.

WiFi is not matter. Matter has mass. WiFi is information transferred over radio waves. Radio waves are part of the "electromagnetic spectrum," which also includes visible light (sunlight, red light, blue light, etc.) and non-visible light (UV light, infrared radiation, etc.). Usually if light is non-visible, it is referred to as radiation, but these are just names. The physics of light and radiation are the same.

Light is energy and energy has no mass. Thus, WiFi is energy and not matter.

WiFi is radio waves emitted by your wireless router and by your computer. It's light. As such, it would be better called energy instead of matter.