Your Wild Joker Casino login can be accessed through the email you used to sign-up for an account. If you forget your password, a reset link will be sent to your email from casino, and you can choose a new one.
If you find that you have no way of retrieving your data, contact support on the website or send them an email, and they should be able to help you out.
They will help you with resetting your password once you verify your identity.