i just want to know that which render setting is best to render HD videos which can be played locally as well as over internet.but should have much clarity and lowest probable size....
There is no "best." You can search here for many threads on the topic, the question gets asked often.
Your requirements are mutually exclusive; they can not all be satisfied at the same time.
H.264 is a good place to start exploring but MP$ and variations are not render settings, they are accomplished using the codec in compression.