iOS 13.6.1 and iPadOS 13.6.1 are now available for download. To get your update, head into Settings > General > Software Update on your iPhone or iPad.
This is a fairly small update that's focused on fixing a few bugs. Apple says it's squashed a bug where unneeded system data files might not be automatically deleted when your available storage is low as well as a thermal management issue that's caused some displays to have a green tint.
Here's the full changelog for iOS 13.6.1:
iOS 13.6.1 includes bug fixes for your iPhone.