Just been introduced to the new places codes with Jo, it really boils down to 2 options as follows:
1. To take the codes to your customer and let them copy and paste them, i think this is too much work for the customer especially if you are getting them to write a review too.
2. you take an iPad or something and copy and paste the code for the customer and get the customer to write the review their and then, not sure if this would be comfortable for the customer but will try.
My suggestion is that you also offer option 3 which could be to provide a logo which you can paste onto invoices etc but it has a field where you can paste the codes. This will allow the customers to not loose a piece of paper as it is within an important document.