If your camera app allows that, it will be in the settings of the camera app.
In the LG camera app on my LG phone, the gear icon lets me pick the SD card or the internal storage, but I do not get to pick the folder name.
Not all camera apps let you pick where the photos are stored. If yours does not let you pick, you will need to manually copy the files to the SD card (not MOVE) and then delete the originals from the internal storage after you restart your phone and verify that the copy was successful.