You posted in the incorrect forum.
Since your phone is running Android "Marshmallow" it should allow for making the SD card "Internal" storage rather than "External" storage. However, if the manufacturer has restricted this option, it won't work, and some do restrict it.
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...