Can't understand why after changing oil the engine would cosume up to 21 quarts of oil without moving truck there is no oil on ground or coolant please help

Is this a deisel? after the oil change the vehicle never moved what so ever-engine never ran? how much oil was put in durring oil change?
generally it it's not leaking it then it's burning it or it was never there in the first place......it won't mistically vanish over night there is something not right with this situation.....now if it is a deisel and you hav been driving it you won't really notice it coming out your exhaust as deisel fuel is basically an oil-pending on amounts actually being burnt. you need to complete an oil consuption test based on mileage and several
tanks of fuel at consistant speeds for same durrations and base it on oil level top up.

Where did you put the oil? Did you check it? Or just keep filling? You didn't put it in the gas tank did you? Gotta know these things.