Why are discounts not displayed in the shopping cart?
Shopify discounts are only applied during the checkout process. For that reason, Shopify does not show the discount information or the discounted total amount in the shopping cart page. This is a known Shopify limitation.
To overcome it, we can suggest two different actions.
First, you can display a message on the shopping cart page to warn your customers that the discount will be applied at checkout. You will find the following option in the 'Discounts' section:
And the message will look like the following:
Second, you can easily skip the cart page and redirect directly to the checkout page with the following option under the 'Global options' section:
We recommend using both options described to maximize your customers' awareness of the discount feature.