To begin with, ensure you have
Rewards for customers
Customer will need to login to your store and click on the loyalty rewards button. In case they are not logged in they will not see their points.
Once logged in, upon clicking the button, your customers will be able to see available rewards in this tab.
Your customer can then click on get rewards / redeem points to redeem their points.
Click on the
button in the confirmation pop-up.
After getting a reward, the customer will have a unique discount coupon code that can be used at checkout for getting a discount.
Note: Points can also be redeemed on the cart page itself. You can
learn more about this feature here