This depends on your settings and where your current notifications are being sent from. 

1. If you are a Shopify user have your Shopify account set to send notifications, be sure to activate your Shopify notifications within Stitch so that notifications are pushed back to Shopify after a package is shipped. Please read the blog post below. 

2. If you are using BigCommerce to notify your customers, no adjustments are needed. Notifications will be pushed back from ShipStation, through Stitch and out of BigCommerce. 

Be sure to check out this blog post about how Stitch interacts with both Shopify and BigCommrece regarding shipping notifications.

3. If you are currently using ShipStation to notify your customers, you don't need to take any further action. ShipStation will continue to notify your customers when packages are shipped.

In all of the above instances, shipping notifications can be triggered automatically. You just want to make sure the system is sending at least one, but not two notifications to customers.