As shoppers, we all want to know where our order is, so most shipping providers offer automatic tracking solutions.
The PickupBird by Digiloop app does not send emails to your customers, but when you forward orders to your shipping provider, in most cases they automatically send a tracking number to your customer as well.
In addition, if your Shopify admin is set up to automatically send your store's customers an email with the tracking number, they'll receive it from you too.