Internal option is. Internal options
First, you need to be using a phone that is running at least Android "Marshmallow" or newer or be able to upgrade to it. Second, you will need the instructions I am including below.
And third, you need a phone that has internal option is been restricted by the manufacturer from making this change.
Which does happen. NOTE: If any of the steps are missing on your phone, or they don't work for you, then you have a phone that either has an older Android version or has been restricted by the manufacturer.
If that is the case, you will not be able to use this information. 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.
Your SD Card will now be formatted as internal storage.
Reboot your phone. NOTE: If you don't reboot the phone, many things may not work correctly, so make sure you do.
When the card is converted to "Internal" storage, it will be formatted wiped and encoded making the cards data only readable by that deviceso anything on it prior would be gone. 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. Once this is done, reboot the device and you can start running things from the card.
If you don't reboot the phone, some things may not work correctly, so make sure you do the reboot.