How can I set up automatic USPS international tracking updates for my customers?

[Johnny724]

1. When I ship an order, does my customer get an email notifying them that the order has been shipped. And does it include a tracking number.
2. If it does include a tracking number, does my customer get tracking updates emailed to them? If not, can this be set up through Shopify?

I have been getting a lot of international returns lately. The orders get to their destination, get held at the local post office. But my customers do not know they have a package to pick up. Is there an app to let me know when a package is being held at a local post office so I can contact my customers? I've been signing my customers up for tracking updates through USPS. They seem to ignore the updates. It is a lot of work to go through orders that are in transit and check on each one of them every day.