Charles Choi has an interesting post on how to make phone calls and bring up a map of a given location from Emacs in the macOS environment. What’s interesting is not that you can do it—it’s Emacs, of course you can do it—but that it’s so easy.
In native macOS apps, you can put your cursor on a phone number and click on it to dial the number (assuming, of course, you have an iPhone and have configured it to use your Mac as a proxy). Similarly, you can put your cursor on a location and click on it to bring the location up in Apple maps.
The interface to both services is the same: you just present a specially formatted URL to the browser and the system takes care of the rest of it. Making a call is the more complicated functionality but only because you have to canonicalize the phone number. That’s done with a (not so simple) regex but the rest is easy.
Take a look at Choi’s post for the details including the code. If you’re a macOS user, often make calls or bring up map from your Mac, and like to stay in Emacs as much as you can, you should take a look at the post.
Of course, the code is for macOS but I’d be surprised if there weren’t similar services in the other OSes.
Update : Added link to Choi’s post.