Download Beta Profiles for iOS, iPhone, iPad, iPod and Apple Tv
Download watchOS 8.7 Beta Profile
Install the watchOS 8 Beta Software Profile.
Go to your iPhone paired to your Apple Watch,and visit to BetaProfile.net for downloading the configuration profile of watchOs 8 beta. Your iPhone will notify you when the profile has been downloaded. Go to Settings > General > Profiles & Device Management, tap the profile and then tap “Install” and follow the onscreen instructions.
2. Update your Apple Watch
After that Apple Watch will automatically receive the latest beta software if you have Automatic Updates turned on in the beta Update settings. You can check for updates, go to the Apple Watch app on your paired iPhone, tap the My Watch tab, then go to General > Software Update.