Older Samsung smartphones can still use the multi-window function. Compatible smartphones include the S series or Notes, but you can check if your device is compatible through the following steps.
Procedure:
Step 1. Go to Settings.
Step 2. Look for Multi-window.
Step 3. If you have the function, simply activate the corresponding switch to enable it.
Once the function is activated in Settings, you will need to add two apps to place next to each other:
Step 1. Press and hold the return key for a few seconds.
Step 2. A menu will on the right side with the list of supported apps.
Step 3. Drag the first app in the top half of the display.
Step 4. Drag the second app in the lower half of the display.
Only some system applications and a few third-party apps are supported.