Walkie-talkie dose not appear on my Apple Watch

It is currently available in Saudi Arabia. This might help you....https://support.apple.com/en-us/HT208917

Hello.

Make sure that FaceTime is installed and activated on your iPhone. Restart Apple Watch.

If you still don't see the Walkie-Talkie app and you're using watchOS 5, contact Apple Support.

Which country you in? As it does not work in all countries