The main steps are divided into two parts:

  1. Go to the Shopify settings page to add the metafield. 
  2. Specify a metafield type to the URL

Set up a URL for metafield in Shopify


  1. Add the corresponding metafield data to the product, which should be a public file link on the Internet.
  2. Select the product you just set up and print it.

For detailed steps, you can take a look at the article here.