Link iPhone to Mac to be able to use WhatsApp on my Mac

The Mac and the iPhone do not "pair" in the common sense as if you would pair ear buds or a speaker to your phone. What is required is that the Mac and the iPhone are both signed into the same Apple ID Account, and in some cases have Bluetooth enabled and/or be signed into the same wi-fi network.

Sync content between your Mac and iPhone, iPad, or iPod touch over Wi-Fi - Apple Support

iPhone Mirroring: Use your iPhone from your Mac - Apple Support

Note that your devices must meet the listed requirements for it to be possible.