Hello Sir, Before providing you the solution for this, I would like to know what is the purpose of providing this unique code to customers, when with every purchase customers are already getting the Order ID which itself is a unique value? While said that there is definitely a way to provide a unique code to each customer which will be different from the order id. I have to code it.
I would like to see the current situation on your site and go through the order process to understand it better if there is already a purchase code being provided to the customers and if yes then which piece of code/plugin is doing so. I would also like to chat with you to understand your requirements better. You can judge my skill by looking at my profile. I am working on woocommerce since 3 years. Kindly contact. I will definitely be able to help you.