What changed: Merchants can now purchase shipping labels through a Shopify Flow action. They can configure order conditions, carrier, service, package type, weight and shipping date. Flow purchases labels as matching orders arrive, making them available to print from the Shipping labels page. Orders outside the conditions remain untouched.
Who is affected
The update concerns Shopify merchants that want to automate shipping label purchases using Flow.
What it means for your business
For businesses using Shopify Flow, this means qualifying orders can receive automatically purchased shipping labels that are ready to print from the Shipping labels page.
What to do
Open the ready-made workflow template in Flow. Configure the order conditions, carrier, service, package type, weight and shipping date for your store, then activate the workflow.
When it takes effect
The feature is available now; the source does not specify a separate effective date.
Source: https://changelog.shopify.com/posts/buy-shipping-labels-automatically-with-shopify-flow