If you are connecting the Samsung Galaxy S6 via USB cable to the computer, then it can happen, unfortunately, that the smartphone is not properly or not at all recognized by the PC.
So if your computer does not recognize the Samsung Galaxy S6 via the USB cable, then it helps to adjust the USB connection type of the Samsung Galaxy S6 manually.
This works according to the following instructions:
To open the USB settings of the Samsung Galaxy S6, you must enter a special code.
Therefore open the Phone app and type via the keypad the following code:
Your phone will now enter the USB settings
Set the mark at "MTP + ADP'. Exit the menu by tapping on "OK". The device might need to be restarted again until the setting takes effect.
You have now set the USB settings on the smartphone. Connect the phone again via USB cable to the computer. It should now be directly recognized and accessed by the computer to the internal memory.