To make the web app feel like a native desktop app, click the three-dot menu in Chrome > More tools > Create shortcut . Check "Open as window." Now you have an icon in your Applications folder that launches WhatsApp in a chromeless window.
Before downloading WhatsApp on your Mac OS 10.10.5, ensure that your device meets the minimum system requirements. These include:
from a trusted archive like FileHippo or OldVersion.com . Search for “WhatsApp Desktop 0.3.552”.
, which natively supports modern macOS features but requires macOS 11 or later