Well, as that phone comes with Android "KitKat" you would not be able to set up the SD card to be "Internal" storage. You would need to be running (or upgrade to) "Marshmallow" to make that change. Also, the phone would have to not had that option restricted by the manufacturer, which does happen. If you can upgrade to "Marshmallow" you can use the instructions below to see if you can make the change on your device.
If you can't make it, for whichever reason, then your only other option would be to move things like photos, music, videos, etc., over to the SD card to free up space. You also may want to clear out say the browser cache, and any other apps that continually add junk to the phone that you aren't using.
How to turn...