Smartphone software does not allow you to run multiple accounts of the same application on one phone simultaneously. Special software has to be used to provide users such functionality and usually these cost heavy solutions for enterprise users. 

Therefore, the customer offered to develop a mobile application so-called "container", in which you can run other users already opened applications, social accounts (VK, Skype, Viber), games, browsers. It is possible to install applications in private mode without the phone's main screen displaying. The application is targeted for usual users, which would like to have several accounts without losing their privacy.