Facebook Inc is testing a feature that will see WhatsApp integrated into the Facebook mobile app, meaning users can switch to WhatsApp directly while on the Facebook app.
The company is testing a new WhatsApp shortcut button on Facebook feed, as seen by select Facebook for Android app users.

Tapping on the WhatsApp shortcut button, which appears prominently in the menu area, opens the WhatsApp app, according to a Next Web report.
Whether Facebook will bring this new shortcut button to all users is not certain yet as only some users who set Danish as their default language were able to see the feature.
It’s not clear what happens when a user who doesn’t have an account with WhatsApp taps on WhatsApp shortcut button.
The company may have plans to bring additional WhatsApp integrations before rolling it out to all; based on the response it sees, according to Next Web.
Facebook acquired WhatsApp in 2014 and has since been exploring ways to make the two services benefit from each other.