Put a polygon or rectangle on the tStop/bStop layer over the specific area on the top/bottom copper respectively. You don't usually need to do that, because pads already have that done for you. EAGLE is flexible and allows you to manually do it for certain use-cases.
But then how do I name the polygon as the pin on the symbol of the device? There is no Name option which means that it won't be shown as connected. How do I fix that?
But then how do I name the polygon as the pin on the symbol of the device? There is no Name option which means that it won't be shown as connected. How do I fix that?
Your question was "How to create exposed pads in Eagle packages??"
and the answer is (as mentioned) "You don't usually need to do that, because pads [i.e. through-hole pads, and smd] already have that done for you".
Your further comment is a different question, but there is no context/explanation of what you're really trying to do, and this thread could end up very long if I just try to guess, so it will be better if you explain the scenario/use-case and then the requirement in detail.
