You can download the software update by heading to Settings > General > Software Update on your iPhone or iPad.
Here are the release notes:
This update includes bug fixes for your iPhone.
– Unlock iPhone with Apple Watch may not work on iPhone 13 models
– Settings app may incorrectly display an alert that storage is full
– Audio meditations could unexpectedly start a workout on Apple Watch for some Fitness+ subscribers
The iPad update fixed the storage error message and audio meditation bugs.