Barcodes before Sunday

Five days. From 1 November the EU wants three product identifiers for every item in a direct-to-consumer parcel under €150. Without them the parcel can be rejected at customs, and you pay for the trip back.

If you ship into the EU with Shopify Shipping or Managed Markets it is stricter still. Shopify will not sell you the label for an EU order when an item is missing them. They put it in the changelog on Saturday, easy to miss in the Black Friday noise: https://changelog.shopify.com/posts/new-eu-product-identifiers-supported-on-shopify-shipping-managed-markets-labels

One of the three is already done, your variant covers it. For the other two you need a barcode (GTIN, EAN, UPC or ISBN, or declare that the product has none) and the manufacturer's model or part number saved as barcode type NS-PID. Your own SKU is fine there too.

Open the bulk editor, find the products with an empty barcode field and fill them in. With a big catalog, don't leave it for Sunday.

Buying labels somewhere else? Ask your carrier or 3PL what they need from you. Same rule, different screen.