Yes!  In QuickBooks, add an item with "Blank Line" somewhere in the product name.  It will look something like this:

In QuickBooks Online:

In QuickBooks desktop:

Note that if you set the item up as a Service, you must have configured your portal to sync Service type items from QuickBooks to the portal.

Once the item syncs to the portal, you will be able to add the Blank Line to an order and a blank line will be shown on the order when you print or email it.