Pretty much any file browser app will allow you to move files (not apps) around. Your phone should even come with one installed, probably called "My Files" or something. Alternatively, there are dozens of apps like that on the Play Store. Barring that, you can even plug your phone into a PC and move them around like that; your phone's internal storage and SD card will show up much like a USB drive might, and you will be able to navigate through the folders.
Click on your camera app to open it and then it is ready to take a picture. When that happens, Go to the black area on the bottom left of your phone (below Mode) and click, choosing "Settings" (Not quick settings). Once there, you see 3 tabs up top, go to the far right one of settings and in the drop down menu, pick storage. Once there, pick Memory Card over Device.