Here is the one I bought. Works great. High quality.

Foam cannon: SudMagic Foam Cannon Pressure Washer Gun - Brass Threaded Bottle (Lifetime Warranty) - Car Wash Soap Foam Blaster https://www.amazon.com/dp/B071G2RW8C/ref=cm_sw_r_cp_api_i_YISeDbR80F0CG

Foaming soap: Chemical Guys CWS_110 Honeydew Snow Foam Car Wash Soap and Cleanser (1 Gal) https://www.amazon.com/dp/B009OTW646/ref=cm_sw_r_cp_api_i_FJSeDb77RYZ1K

The soap is great. Highly rated and smells nice.

The foam cannon changes everything when washing your car!

Edit; I’m fairly sure that almost any foam cannon would work, but the one I got is a good one as far as I know.

You need a foaming type of soap. Can’t use your old on I think... but you can try.