I can’t pair my Apple Watch

Without knowing anything else (error messages, etc.), perhaps these articles will help:

Set up your Apple Watch - Apple Support

If your Apple Watch isn't connected or paired with your iPhone - Apple Support

What model of phone is it and what version of ios is it running?

What model of watch is it and what version of WatchOS is it running?.

What troubleshooting steps have you tried?.

What errror messages are you receiving?.