Galaxy 3 tablet owner

Solution
If you are just wanting to move photos, video, contacts, music, etc., over to the SD card, you would need to go into the individual apps that you created and/or downloaded them in and change the settings to use the SD card.

Now, however, if you are wanting to make the SD card "Internal" memory rather than "External", so you can run apps from it, that is a whole other story.

First you will need to be running at minimum Android "Marshmallow". Second you will need to have the instructions I am including below. And third, you will need to have a device that the manufacturer has not restricted (which happens a lot). You will know if it is restricted when you try to use the instructions. If any of the steps are missing on your device, then...
If you are just wanting to move photos, video, contacts, music, etc., over to the SD card, you would need to go into the individual apps that you created and/or downloaded them in and change the settings to use the SD card.

Now, however, if you are wanting to make the SD card "Internal" memory rather than "External", so you can run apps from it, that is a whole other story.

First you will need to be running at minimum Android "Marshmallow". Second you will need to have the instructions I am including below. And third, you will need to have a device that the manufacturer has not restricted (which happens a lot). You will know if it is restricted when you try to use the instructions. If any of the steps are missing on your device, then it is restricted.


How to turn the "External" SD card into "Internal" storage on "Marshmallow".

NOTE: Please be sure you start with a blank SD card. It needs to be blank because when the card is converted to "Internal" storage, it will be formatted (wiped) and encoded (making the cards data only readable by that device).

1. Go to device “Settings”, then select “Storage”.
2. Select your "SD Card", then tap the “three-dot menu“ (top-right), now select “Settings” from in there.
3. Now select “Format as internal”, and then “Erase & Format”.
4. Your SD Card will now be formatted as internal storage.
5. Reboot your tablet.

NOTE: If you don't reboot the tablet, many things may not work correctly, so make sure you do.


How to turn the "External" SD card into "Internal" storage on "Nougat".

IMPORTANT NOTE: Be sure you start with a blank SD card. When the card is converted to "Internal" storage, it will be formatted (wiped) and encoded (making the cards data only readable by that device), so anything on it prior would be gone.

1. Go to "Settings", and then select "Storage & USB".
2. At the bottom of the list you should see the SD card's details, including the option to format it and make it "Internal" storage.
3. Once this is done, reboot the device and you can start running things from the card.

If you don't reboot the tablet, some things may not work correctly, so make sure you do the reboot.

 
Solution