I heard that Lightroom Mobile can take photos using DNG format. Does this increase the photo somehow or am I better off sticking with JPG using my iphone 6s?
This is not yet supported on iOS. It works on Android. Apple is working on giving raw support to apps in iOS in the next release which would happen soon. When it comes you're much better off shooting raw (i.e. dng format) than jpeg as that will give a lot more editing freedom just like it does on full-size cameras.
sweet thanks. My only fear is that this raw format will only work in apple photos not lightroom mobile.
It's supposed to be standard compliant dng so should work everywhere.