If you have a high-end device then by all means download the highest possible quality versions, but remember that the higher the resolution the bigger the file: if your phone or tablet doesn’t have much free space, YouTube videos will soon fill it up.
You’ll see video and audio formats and different quality and resolution options for each. The next thing you’ll see is a list of formats. When you've chosen a video, tap the red button, choose your settings and you're ready to start (Image credit: Devian Studio) 3.