When placing a Walmart pickup order as a non-us resident traveling the us you need to specify a US billing address and US phone number. How should you use this service without those things. From experience if you order using the address and phone number of your hotel you will end up with your order cancelled.
Best buy in contrast mentions on their order form that you have to use a special address they provide you with if you're an international customer. Does something similar exist for Walmart?