The Shopify interface does not discretely handle Tips like other restaurant Point of Sale systems do.  The  Tip item(s) need to be associated with a Tip Category(s) in Shopify.  This will allow the tips to be pulled out for separate mapping in your Shogo account.

Shogo will recognize the Tip Categories once they are used.  If you do not see the Tip Item in Shogo or your accounting file then that Tip item has not been used in a sale (at least from your Shogo start date).