The Settings app on the iPhone is what you need: choose General, followed by Software Update. Then, choose Download and Install, and it’ll be on your phone shortly. It’s a large-sized update, as these things go, weighing 1.98GB on my iPhone 17 Pro Max. It downloaded and installed quickly — less than 20 minutes total.

Finally, both iOS 26.3 and iPadOS 26.3 are introducing a feature for some newer devices with Apple’s in-house C1 and C1X modems: a “limit precise location” toggle that Apple says “enhances your location privacy by reducing the precision of location data available to cellular networks.”