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

You created this account and you are responsible for the security of your account unless the general hack happens on the exchange. It is not safe to use commonly known passwords on the financial sites and your account is the only affected due to your careless behaviour on the crypto exchange.