what i need to do that?

or any armor great like enclave, brotherhood, etc

Ask around in the Citadel. Someone--I forget the NPC's name--can give you power armor training. Or, after escaping Raven Rock, you can return to the Citadel for the assault on the Jefferson Memorial. You will be given your choice of power armor suits. Another alternative is to complete Operation Anchorage. A very nice suit of wearable power armor awaits you at the end of that dlc.