Hey @Yumshi, thanks for your post!
At the moment, it is not possible to create discount codes for specific fulfillment methods (e.g. collection, delivery, and pickup).
But I think it's a great idea though! I'll make sure to pass your feedback over to our team.
In the meantime, you can Create Online Discounts with Vouchers if you have a Square Online website, which your customers can use at checkout. Or, you can Create and Manage Discounts for your Point of Sale for in-person payments.
Let me know if you've any further questions!
