How to watch videos in 144p, 240p, 360p, 480p, 720p on YouTube app? While watching videos in browser it shows me options of 144p, 240p, 360p, 480p, 720p and so on. But on YouTube app for Android I only see option of HD/HQ (I assume its High Definition / High Quality).

How can I watch videos in 144p, 240p, 360p, 480p, 720p on YouTube app?
You can't. Those quality settings only apply to the desktop version. Mobile apps use a different set of videos, which are already optimized for mobile devices, and have two different quality settings, regular and HD.