Redeem a promo code | Seamless Help | Contact Seamless | Customer support On the Seamless website, you'll need to select the link that says "Add a promo code." A field will appear for your code. Within our app, scroll down to find the promo code field. Enter the code from your email (we recommend the copy/paste method for accuracy) Click or tap "Apply". We'll adjust your order total to factor in the discount.