SKULabs automatically detects virtual products on most channels.
On Shopify you can uncheck the "This is a physical product" checkbox in Shopify and they will automatically be excluded when found on new orders going forward.
On Big Commerce, you can change an items Product type to select Downloadable product.
https://support.bigcommerce.com/s/article/Creating-Downloadable-Products (Provide no download URL/file if you don't want it to be downloadable)
If it's not supported by your sales channel by default, reach out to our team with an order number for the best advice on how to exclude a product from your orders using other means or customizations to our sync with your store.