Skipping and Passing items are often confused.

If you want to visually verify an item that is not barcoded or has a damaged barcode you'll use the Pass (Click-Scanning) feature.

If you have specific items in your inventory that are included as line items in the order but are optional, meaning the order should not be held for them, you can set them to be Skipable. 

Setting an item to Skipable allows the packer to scan the SKIP action barcode when the item is suggested for scanning. This will remove the Skippable item from the order.

Items like freebies or gifts that may be part of an order, are often set to be Skipable. That way, if they happen to be out of stock, the packer can scan the SKIP barcode to continue. 

Items can be set to skippable by enabling the switch shown below:

The setting can also be enabled for products in bulk by importing a CSV that has the value ON mapped to the "Is Skippable" field.