Laser help needed

Could do with some advice.

My Son has been running the CNC router, that I built, for the past three years. In the main V Carving signs and placks on wood.
He has now asked if I could add a laser head to it to engrave designs on wood.

I have absolutely no knowledge on lasers. What type and power would be required. Presumably it would need a power supply and cooling.
Are there suppliers that offer all the bits required.

Any advice would be most welcome.

Thanks
George