Finding an open area with a clear view of the Moon is essential for getting decent photos of the Supermoon or any other celestial event, for that matter.
In order to maintain your shot's stability when recording a celestial event, mounting your smartphone on a tripod can help a lot.
Since the moon is only about 384,400 kilometers away from the earth, using the flash is pointless. But by illuminating the surroundings and surrounding dust, it will undoubtedly damage it.
You are using a slow shutter speed and photographing in low light, as was already explained.
So, use the camera app's built-in timer function to further prevent any undesired tremors when pushing the shutter.
High Dynamic Range, or HDR, is a technique that can help you capture a more accurate and detailed image of the moon.
Digital zoom should never be used when taking pictures of the Moon since it degrades the resolution and clarity of the images. Use the telephoto lens instead.
The majority of contemporary smartphones include high resolution sensors, such as 64MP, 50MP, or 108MP. To snap the picture, if possible, switch to the full resolution mode.
Make sure to long press the Moon and lock the focus and exposure while taking pictures of it.