Well, it is going to depend on what version of Android it is running. If it is running what it came with, which should be "Lollipop", then you can't move them over. However, if you have upgraded to, or can upgrade it to, "Marshmallow", then you 'may' be able to make the change. I say 'may' because it is possible the manufacturer has restricted this option on the device. 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...