How To Turn On "Move apps to Sd card in Android5/6/7/8/9/10/11/12/13?

From Settings(if Feature is available in Smartphone).
Step 1. Just open settings and go to developer option(click here to check how to turn on developer option), and look for force allow apps on external storage, and just turn it on.

Step 2. Then go to Settings > Storage > SD Card > Format Sd Card as Internal.

Step 3. Long press on a app icon and go app info > Storage and cache > Change, Then change to SD Card.

Through ADB or platform tool(SDK tools).
Step 1. Download platform tools,Click to download.

Step 2. Extract the file and open CMD in that extracted folder.

Step 3. Go to developer option and turn on usb debugging,(open setting > Search Developer option > find USB debugging and turn it on(click here to check how to turn on developer option)).

Step 4. Connect smartphone with usb to your laptop/computer, and click allow on smartphone when the dialoge box appears.

Step 5. Type the following Command with instructions.

adb shell
sm list-disks
// HERE YOU GET YOUR DISK ID, SOMETHING LIKE "disk:179,64" - REMEMBER THOSE NUMBERS
sm set-force-adoptable true
// IN NEXT LINE, SIMPLY PUT THOSE NUMBERS AFTER "disk:" AND ALSO AFTER WORD "mixed" TYPE PERCENTAGE OF SPACE LEFT AS EXTERNAL, SO IN MY CASE:
sm partition disk:179,64 mixed 60
// IT TAKES TIME. BE PATIENT. WITH THIS LINE I TRANSFORMED WHOLE EXTERNAL SD INTO 40% OF INTERNAL AND 60% OF EXTERNAL
sm set-force-adoptable false