Hello,
You are facing an interesting challenge. I have few queries on your business model : -
1. How your business works, does the delivery boy has to buy the requested products/items and then deliver it to customer, in that case you don't hold up any inventory.
2. Do you have fix set of local stores from where the delivery guys can buy
3. In this proposal are you looking for business solution or you also need the fully functional app. As I can only provide business solution.
It would be great, if you can answer this questions through Chat, as solution is heavily dependent on your business model.
I have some solution in mind, which need to be first vetted with the existing business model.
Looking forward to hear from you.
Regards,
Shubham