Since the desktop app no longer supports macOS 10.13.6, WhatsApp Web is the most reliable and recommended solution. It provides nearly all the features of the desktop app without requiring a software download.
If you try to log in and WhatsApp says "This version is outdated," this workaround has been blocked by WhatsApp servers, and you must revert to Option 1 . whatsapp mac 10.13 6 download
To download WhatsApp on your Mac running macOS 10.13.6, follow these steps: Since the desktop app no longer supports macOS 10