To create coupons and discounts codes, open your Shopify store’s admin panel, and click on Discounts.
After clicking on Discounts, a new page will appear. Now, click on Create discount code.
When you click on Create discount code, you will go to next page. At this page, you will create manual code as well as generate code by clicking on Generate code. You can also add values, requirements and other settings related to discount codes.
After creating coupons and discount codes, first Save discount code from the right bottom corner of your screen and also click on Save button at the top right corner of your screen to save all the changes.