Since that phone should be running Android "KitKat" setting the SD card as "Internal" rather than "External" storage can't be done. You would need to be running at least "Marshmallow" to do it.
Now if you can somehow update the phone to "Marshmallow" then follow the instructions below. But do note that not all phones, running "Marshmallow" or not, will allow for changing the card this way. Some manufacturers have restricted the option.
Be sure you start with a blank SD card as well. This is because when the card is turned "Internal" it is formatted and encoded. This wipes any and all data on the card before and makes the card only readable by that device.
How to turn external SD card into internal storage on "Marshmallow".
1. Go to...