Hello, apologies as I have seen other people in this forum have the same issue, but I have been unable to figure out the fix. My site (all pages) is having an issue on iPhones ( I am not sure about Android) in that a large amount of blank space shows. If anybody can offer advise (Im not a web designer) on how to fix, it would be greatly appreciated.
Try hiding the overflow of your sections and see if that helps. I looked around and it looks like you might need to hide overflow in your navbar and a couple other areas.
As jdesign stated there is an item on your page that is wider than the viewport itself (the screen). If you take a look at your site you can see that the image section has a width of 500px. If you change that to 100%, the section will now cover a 100% of the screen: