When you change the SD card to work for apps, etc., you actually make the card "Internal" storage, rather than the typical "External" it is normally.
That can make it a bit confusing when you are checking the apps to see where they are. Now, it is also possible that the apps are on the true "Internal" storage rather than the card. Unless you set up the card to be "Internal" you won't be able to run apps from it. All other files can move over to the SD card, but apps take specific changes to work from a card.
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 phone.
NOTE: If you don't reboot the phone, many things may not work correctly, so make sure you do.