This is an accepted solution.
Ash here from the Shopify team. Thank you for reaching out with your question!
I understand you've received an order stating shipping isn't required, and you're trying to determine how to proceed. I'm happy to help with this! Without taking a closer look at the order in question and the product(s) in the order, I can't say for certain what's going on here. With that said, I have a fairly good idea of what happened, and I'll get you to check if my theory is correct on your end.
When an order contains products that are not marked as "physical products", then the system will recognize them as not requiring shipping, and thus the shipping step of the checkout will be skipped. This also means that there will be no option to buy and print a shipping label for the order, since the system determines these products are digital or non-tangible. So, our first step is to check if the product(s) in the order in question are marked as "physical products" or not.
To check this, head over to the order page for the order in question, and click on one of the products titles. This should take you to that products page in the admin. Scroll down on the product page to find the "Shipping" section of the products settings. There you'll see a checkbox, and in order for the product to be considered a "physical product" and require shipping, that box must be checked (note: this needs to be checked before an order is placed for the order to include shipping). Here's what that checkbox looks like:
If the product(s) in the order in question look like the above screenshot, and are not marked as physical, then that explains the issue. To make sure this doesn't happen again, ensure all products that require shipping are marked as "physical products" in your store. You can check this setting, and make changes to multiple products at once using the Bulk Editor for Products.
To resolve the issue, there are a couple options. Whatever resolution you choose, I suggest reaching out to the customer and explaining the situation so there are no surprises. One option is you can cancel and refund the order, and have the customer replace it after updating the product. Another option is to create a draft order that does require shipping. You can fully discount the product, and then either mark the shipping cost as paid (eating the cost of shipping for your customer) or use the draft order to send them just the invoice for the shipping cost. You should then be able to fulfill that order as you normally would, and purchase and print a shipping label. Once the product is off to the customer, you can go into the original order to mark it as fulfilled.
If the product(s) in the order were already marked as "physical products" before the order was placed, please reply back here and let me know. I'll want to take a closer look into this situation if that's the case. Also please feel free to reply back here if you need any further assistance or clarification with the above information!