If you have a Tesco.com account, then you can just sign in to Tesco Pay+ with your Tesco.com username (email address) and password. Your Clubcard number will be automatically linked from your Tesco.com account to your Tesco Pay+ account.
If you don't have a Tesco account, then we'll create one for you when you register with Tesco Pay+, either in the app or here. If you've already got a Clubcard number, then you can enter this during the sign up process. If not, then we'll give you a new Clubcard number automatically.