To create a site-wide discount:
Go to Marketing > Coupon/Discounts in your Admin Area
Enter a name for your discount in the Discount Name field.
If you want the discount to be automatically applies, you do NOT need to select Coupon and add a Coupon Code
Select Percent Off Entire Order from the Discount Type menu
Fill in Discount Value with the discount amount (for example, “10,” if you want to offer a site-wide 10% discount)
You can also configure other options for your discount, such as making it applicable only for a limited time (by setting a start and end date for example). All of this can be done within the detail edit page for the coupon/discount.
The discount will be displayed and applied on the customer’s shopping cart page.