Question: how to transfer files from internal storage to sd card samsung s7?
Answer: Tap Apps icon.
Tap My Files. If you put all Samsung apps in one folder, open that folder first. ... 
Select Internal Storage.
Find and tap DCIM folder.
Tap Camera app.
Tap and hold the photo you want to transfer to SD card.
Tap More options at the upper right (three dots).
Select Move to begin the transfer process.