https://wccftech.com/apple-seeds-release-candidate-builds-of-ios-14-3-ipados-14-3-watchos-7-2-and-tvos-14-3-download-now/

Today, Apple has seen fit to release the release candidate build of iOS 14.2, iPadOS 14.3, watchOS 7.2, and tvOS 14.3 to developers and public beta testers. The update arrives a week after the third beta was released to developers. If you're a developer or a public beta tester and want to check out the release candidate builds for yourself, you can do so through the Apple Developer Center.

As mentioned earlier, iOS 14,3 and iPadOS 14.3 release candidate build can be downloaded on your iPhone and iPad through the Apple Developer Center. In addition, the build can also be downloaded over the air. Be sure to install the appropriate configuration profile from the Developer Center.