Last week Apple released 10.0.1 (10.0 shipped on some new devices from the factory but 10.0.1 was the publicly downloadable release). Today they are releasing a minor bug fix update which fixes a couple of minor crashing issues and fixes an issue that prevented some people from being able to use the remote control buttons on the new Lightning EarPods that shipped with Apple’s new iPhone 7.
You can download the update on your iPhone, iPad, or iPod Touch by visiting Settings > General > Software Update. This is a rather small patch so it should take no longer than about 5 or 10 minutes to install.