Please follow the steps for assign a production Shop as a Supplier for any Shop

Login to Back Office > go to ‘Settings’ from the left menu > select ‘Admin Settings’ from the submenu of ‘Settings’ > select ‘Assign Supplier To Shop’ tab > select production shop in the drop-down option of ‘Select Supplier’ and select role in the drop-down option of ‘Select Retailer’ > as the last step click on ‘Save’ button.