Well, it is going to depend on what version of Android is on the phone. If it is anything less than "Marshmallow", then running things from the SD card (apps) won't work. Only individual apps that say you can move them, which there aren't many, would work. To do what you are wanting to do requires some changes, which I will include the instructions to below. But it all hinges on the phone running on "Marshmallow" and the manufacturer not having restricted the ability to do this on that phone. It happens.
How to turn 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 phone.
NOTE: If you don't reboot the phone, many things may not work correctly, so make sure you do.