Rearranging your icons so they’re in alphabetical order and removing folders makes finding apps a little bit easier, but it’s an almost impossible task to do by tapping and dragging. However, iOS offers a somewhat hidden solution.
Open the Settings app, then tap the General heading and tap the Reset entry within the list. Tap Reset Home Screen Layout. This will restore the first home screen to a ‘virgin’ state, showing all the Apple apps as if you’ve booted for the first time, then it will rearrange all your other apps into alphabetical order, removing any and all folders in the process.