Keep in mind that this is a developer beta, not the public beta release. The latter should be released within the next day or two. If you don’t want to wait for the final version of iOS 14.4 to be disseminated, you can sign up to join the Apple Beta Software Program. Just keep in mind that beta versions of software are often buggy. If you don’t mind using the public beta version until the stable software is disseminated, go to beta.apple.com on your iPhone or iPad. Tap on Sign up and use your Apple ID to create and download your beta profile. Make sure it is enabled by tapping on it. Next, you reset your device and download the latest beta by going to Settings > General > Software Update.