The Camera app on your iPhone can take three kinds of video and at least three types of photos, depending on which iPhone model you have. The Camera app interface suggests that you switch between these types or modes by tapping or swiping on the labels below the viewfinder. These labels are small and can be difficult to swipe accurately. If you’ve found moving between modes frustrating, you can also swipe left or right on the entire viewfinder, which has the same effect as swiping on the labels but with a much larger swipe area. This is usually how I switch between the different modes, just swipe left and right in the viewfinder.