Linux Mint 20.3
WhatsApp 2.22
On my Google Pixel 3 smartphonoe (Android) I has application Whatsapp and success call. Nice.
I start on Linux desktop application WhatsApp. And I can't call. Button "call" not exist.
The Whatsapp support article About desktop calling says this:
Desktop calling is supported on:
- Windows 10 64-bit version 1903 and newer
- macOS 10.13 and newer
It seems you're out of luck on Linux (at least for the moment).