I want to add a file upload field on checkout page in woocommerce.I have added it but when I click on "Place order" button and try to check post values,$_FILES array is empty while other fields on the same page ,same form are coming with respective values.I am using response using print_r().This issue also had been asked in below thread and explained well.I have exactly same problem as in this thread.

How to upload a image in woocommerce checkout page and link it to the order

Any help highly appreciated.