Sir can I take creatine monohydrate at home when I am not going for workout. Or is it a waste to take creatine on non workout days?
Yes, you take creatine everyday, not just the days when you go to the gym.
You have to understand your muscle don't grow during the workout, they grow from the rest, recovery and nutrition you give them after the workout. So sleep, food and supplements are just as important on rest days as they are on workout days.
For the best form of creatine checkout https://www.trulyhuge.com/creatine.htm
Best,
Paul