Well the card would only be used as "External" storage. So only if you moved things like photos, videos, music, etc., to the card would anything go there, or if you set up specific apps to save content there (like downloads). However apps themselves would not be able to be put on and run from the SD card unless you are 1. Running Android "Marshmallow" or can upgrade to it and 2. the manufacturer hasn't restricted this option on that device.
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 “Format as internal”, and then “Erase & Format”.
4. Your SD Card will now be formatted as internal storage.
5. Reboot your tablet.
NOTE: If you don't reboot the tablet, many things may not work correctly, so make sure you do.