Well the for the files from the card to the phone part, I would have to ask what kind of files and how are you trying to move them? These make a large difference.
In regard to the moving apps to the SD card, well, depending on your device, you may not be able to. First you need to be using a device that is running at least Android "Marshmallow". You also need to have a device that has not be restricted from doing this by the manufacturer. Yes that does happen, a lot. And you also need the instructions I am including below.
NOTE: If any of the steps are missing on your device, or don't work for you, then you probably have a device that was restricted by the manufacturer.
How to turn the "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.
How to turn the "External" SD card into "Internal" storage on "Nougat".
IMPORTANT NOTE: Be sure you start with a blank SD card. When the card is converted to "Internal" storage, it will be formatted (wiped) and encoded (making the cards data only readable by that device), so anything on it prior would be gone.
1. Go to "Settings", and then select "Storage & USB".
2. At the bottom of the list you should see the SD card's details, including the option to format it and make it "Internal" storage.
3. Once this is done, reboot the device and you can start running things from the card.
If you don't reboot the phone, some things may not work correctly, so make sure you do the reboot.
LG Stylo 2 K540. Recently updated to the 13d software. I've tried formatting the external SD card both ways as you explained and neither worked. I cannot delete files from the external SD card. I've gone as far as removing the card and installing it in both my laptop and my desktop and the files show that they were deleted but as soon as I put the SD card back in the phone and mount it they reappear in the directory. I've also completed a factory reset on the phone with the SD card installed and the files are still there!!