Today Apple issues iOS 10.3 to the public, if you are running any of the 10.3 betas you will find you cannot see the update, to get this simply follow the guide

Step 1: Open Settings → General → Profile.
Step 2: Tap Delete Profile under iOS Beta Software Profile.
Step 3: Enter your passcode, and tap Delete again to confirm.
Step 4: Reboot your iOS device.
Step 5: Open Settings → General → Software Update to check for the iOS 10.3 update.