For WhatsApp Desktop, macOS 10.15.7 (Catalina) or later is supported.
Here are some tips and tricks to get the most out of WhatsApp Web on your Mac OS device: whatsapp web mac os 10157 link
Open a supported browser on your Mac. Google Chrome is highly recommended, though Safari, Firefox, or Brave work well. Navigate to Site: Type web.whatsapp.com in the address bar. For WhatsApp Desktop, macOS 10
Then, the interface changed.