If you want to claim an offer in a casino you have never played before, then yes - opening the account is a must. When you wish to use the bonus offered in a casino where you have played before and you have an account, then you simply sign in.
It is important to note that Welcome offers are valid only for new players. Usually, there is a deadline for claiming such a promotion. Meaning you might be eligible to claim this offer even if you made your account earlier. But that all depends on the rules of the individual operator.
How to Claim an Offer?
Claiming an offer requires a few simple steps:
Go to the Casino page and find the offer and the casino best suited to your needs
Click on the 'Claim Offer' button and you will be redirected to the chosen casino
Register or sign in and enjoy the perks of the selected offer