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

I canmot really blame you or the website, until i investigate where the cause came from because:
1. It could be you allowing hackers in for not setting 2fa or the hacker hacked your phone to get your pwords and 2fa
2. It could be that the website was hacked.
In the second case, it won't be only one account, it is usually a pack of accounts with stolen funds.
In any case. STAY SAFE