Pairing Apple Watch
Watch is asking for iCloud and password.
after asked me for more information to go to support.apple.com/kb/TS4515
Apple Watch Series 4, watchOS 9
Question marked as
Did you try to fill in the Apple ID and the password that has been used to set up the Apple Watch?
How to remove Activation Lock - Apple Support
In case you have forgotten Apple ID password, you can reset the password:
If you forgot your Apple ID password - Apple Support
If this does not work, and you have proof of purchase documentation, you can start an Activation Lock support request.