Cannot message on messenger

Hello mykola2, 

Thank you for contributing to the Apple Support Communities. 

The Apple Watch QuickPath keyboard is not available in all languages and requires either an Apple Watch Series 7 or Series 8.

Please check over the following Apple Support article to confirm that your watch is compatible with this feature: Send messages from Apple Watch. If you continue to notice an issue using this feature, please try the following troubleshooting steps: 

1. Restart your Apple Watch.
2. Update your Apple Watch.
3. Confirm that a Bluetooth connection is not enabled unexpectedly: Use a Bluetooth keyboard with VoiceOver on Apple Watch. 

If the troubleshooting above does not help you reach a solution,  please contact Apple Support directly for more help. 

All the best!  

You are obviously referring to Facebook Messenger and if that is the case, Facebook (Meta) has NOT incorporated the keyboard into the Messenger App for Apple Watch.

You should reach out to Facebook about this. Apple doesn't own the Messenger App.