if I've created account/wallet on coinbase or any other exchange then my account is hacked and my coins/money lost who are responsible for it
The Exchange where I've created account

is it my mistake

what's you thought about it

and how i make my account safe

It's a mistake that goes both ways my friend. In this world, frauds and tricksters will do whatever they can to get an advantage, even if it means stealing other's hard earned investments. It could be a liability in law on the hacker's end which could get him behind bars. But it is also your fault in a sense since you did not take enough precaution. What I could highly suggest moving forward is for you to be mindful of where you login or register.