Your iPhone 11 is already a very capable camera. By adding lenses and filters, you can do more with it. The ULANZI 5-in-1 iPhone 11 Multi-Lens Case can help. It comes with 4 lenses (Macro, Fisheye, Telephoto) that you can switch quickly thanks to the slide and flip up design. A lens cover is available to keep scratches and dust away.
This case comes with 180-degree fisheye, 2X telephoto, 10X macro and 20X macro lenses and a CPL filter. Costs under $40 at this time.[where to get it]