If you have a specific product that has a set weight, or if you ship one product on its own and want to include the weight of the packaging, setting up a rule to automatically apply weights to that SKU will help you save some time.
For example, “Apply Weight to SKU…“
Set the "IF" condition to Item SKU and select your logic. For example, Is Equal To will apply to all SKUs that exactly match what you are typing in, and Contains will apply to all SKUs that contain what you type in. From there, type in the SKU or partial SKU that you want this rule to apply to.
Set the "THEN" action to Add to order weight and enter in the weight of the product.