For multi-window mode in your smartphone, it would be better to use the free Taskbar application
But before you install it, you must do the following:
1. Go to the main settings menu of your smartphone and turn on the “For Developers” section in it. You can do it this way:
To do this, you need to do the following:
1. Open Settings
2. Go to the "System", which is located at the very bottom
3. Next to the item “About the tablet” or a similar name for the smartphone.
4. Locate at the bottom “Build Number
5. Click on it about 10 times, after which the developer options will be available
2. In the "For Developers" section, activate the option "Resize in multi-window mode
3. Restart your gadget.
4. Now install the taskbar downloaded in advance and run it
5. Clear the list of recently launched applications and click “Home”
On the smartphone’s desktop you will see a taskbar application panel button, clicking on which you will be able to launch any of them in a separate, floating window.
This feature is only supported on Android devices that have at least 2GB of RAM and 16GB of internal memory installed.