As someone who is an avid online shopper, I do a great job of helping to keep the post office in business. Surprisingly, it's very rare that my packages get lost in the mail. But, I did have an incident, recently, that caused me to look around on the USPS website to try to figure out how to file a lost claim.
While searching the website, I learned that the USPS has a new (to me) feature called "informed delivery" which shows you a scanned image of your letters that are out for delivery, as well as tracking info on packages that are on the way. I don't think that a lot of people know about this even though it was released in 2017. If you're interested, you can sign up for this free service by clicking here.
I've been using it for a few weeks now and it's great! Check it out.