We'll create fresh WordPress site with File Upload For WooCommerce installed. You have 20 minutes to test the plugin after that site we'll be deleted.
This plugin as the name shows allows the user to upload the file either on single product page or checkout page. It’s upto the Admin who can choose where the file upload button should show. Admin can also enable/disable this option . Admin also have the option to enable the multiple files or single files upload restriction by the user. Admin can also restrict the user to must upload file to continue.
There would be a folder create in your wp-content/uploads/file-upload-for-woocommerce where all the files will be uploaded and user can also manage the files from the admin side. It also has the option to show the upload file button on specific products and on different locations on checkout page too.