Most casinos will feature their main welcome offers on their homepage, or you can check their promotions page which will feature all of their current offers. The bonus cash would typically be credited to your account straight away, ready to play. As the name suggests, you won’t need to make a deposit to claim the bonus, usually you’ll need to enter a bonus code or opt into the promotion.
Players will normally need to register an account with the casino and may need to enter credit or debit card details (don’t worry, no money will be taken at this stage). The casino will hope that you’ll enjoy what you see and deposit real cash into your casino account to carry on your patronage with them. To attract new players some casinos will offer a no deposit bonus to get players to sign up and try out their casino for free.