1. Go to Marketing > Coupons and click Add Coupon (or open /admin/coupons/0).
2. In General, enter a Name (internal label) and the Code customers will type. Optionally set an End Date and the Available Quantity (defaults to 99999). Decide whether the coupon should Auto Apply Coupon to Cart, Show as Suggested Coupon, be Is Active?, or Apply Discount to Recurring Subscription Rate.
3. In Coupon Limits, choose any restrictions: Limited One Use per Customer, Limited to First Time Buyers, Can be used with other coupons, Exclude Meals from Coupon, Limit Per User, Limit Per Membership Plan.
4. In Discount Rules, pick the Type, enter the Value and the Minimum Cart Value Required ($). Add Dynamic Custom Rates tiers if you want a bigger discount at higher cart values.
5. If you sell extras, optionally pick a complimentary Extra Item under Offer Extra Items.
6. In Delivery, toggle Offer Free Delivery? and/or Discount Applied to Delivery Fee?, then tick the ordering systems under Allow on.
7. Click Save. You are returned to the coupon with a "Done!" banner.

Both Name and Code are mandatory ("Empty Name!" / "Empty code!"), and the code must not already exist.