A free program for Android, by HoysGame Studio.

Android devices supporting 21 api and above can download and install Dual Multi Space – Dual App apk, which has a PEGI 3 content rating.  Multi Space is made for users who log in to more than two accounts (many accounts) of the same app on a single phone. You may easily acquire dual Facebook and dual WhatsApp.

This app allows one phone, multiple accounts, and simultaneous online use. It is compatible with most Android apps, including a variety of games and social media apps. Powerful app cloner to create many accounts or parallel apps and can use two or more WhatsApp accounts to maintain a balance between work and life.