Following the integration, messaging services on Facebook, Whatsapp, Instagram and Messenger can be used together.
The integration has reportedly been planned and in the works by Facebook for quite some time. The effort was also reportedly undertaken through an initiative of Facebook CEO Mark Zuckerberg himself.
While the work on the three apps are similar, the biggest undertaking will be to minimize impact on user data policies.
The integration efforts will estimated reach completion by end if this year 2019 or within the next year.