Doubling bitcoins is possible but its pretty hard, with websites its without any doubts not possible but that is already clear.
With trading there are some options but it also has some big risks to be honest.
it is really hard for sure in my opinion, i think it would be better to just hold it because it is impossible to double it safely
Yeah its never easy to double your money and if someone promises you to double your coins in quick time then surely they are making false promises and you will surely loose everything that you have.