I sent a gift card to a customer and it says the numbers are invalid when she tried to order
Welcome to Seller Community, @Karm, and thanks for your post.
Is your customer using it to order online? Do you know if they are typing in the gift card number or pasting it in?
Yes they are in the coupon section
By that you mean a section on your website? What is the address of your website?
Square Community
Square Products