Every mobile app has that button. You tap it, a tray slides up from the bottom of the screen, and there's WhatsApp, Messages, AirDrop, Notes, Discord, whatever you happen to have installed. For years that tray was native-only territory, and the web's answer was a row of brand icons opening twit...
Source: [Dev.to](https://dev.to/kaikina/the-native-share-sheet-is-three-strings-and-two-fallbacks-3m3i)