Well most apps won't move to a SD card. Not unless you are using at least Android "Marshmallow", have a device that allows for the changes to be made to it (using the instructions below) and hasn't been restricted by the manufacturer.
Also, certain apps won't move. Apps that came with the phone, like the main messenger, gallery, etc., won't move to a card.
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"...