When photographing a fireworks display, I find it best to figure out where the fireworks will be launched from (and where they’ll end up in the sky), try to get your background as clutter free as possible, and potentially position oneself for a pleasing foreground.
In Bay City, Mi. one of the more popular places to photograph from is atop one of the nearby bridges. Such a vantage point affords you a great view of the show and between the river, boats, and reflections on the water, the foreground is usually pleasing. Regardless of camera type/ brand, you're going to need manual control and a tripod. If you’re on a bridge, it’s best to position oneself over a main support structure. Otherwise passing cars will cause potentially unpleasing vibrations in the final image.
Typical Camera settings:
Shutter 5-15 seconds
ISO – 100-200
aperture f/9 - f/13
I primarily use a DSLR, but decent results can be had as long as you’ve got manual controls on your camera.
While you can’t manipulate the aperture on smartphones (I'd love a smartphone with this capability), you can usually adjust the ISO and Shutter. So keeping the ISO as low as possible is a must since most smartphones have a pretty fast base aperture of 2.2-2.8. As far as lenses go, smartphones tend to be a bit wide at ~22mm. This is nice for selfies and such, but can make fireworks look diminutive, so it’s best to get closer than further. If you you’re finding yourself getting too much light in your shots, try shooting with a faster shutter or perhaps getting an ND filter to stop down the amount of light entering the sensor.