Depends on what you plan to do and the type of equipment used. For most using our class of equipment a waiver would suffice for altitude and nocturnal operations. For attempts at BLOS and extended operations in specific airspace a CoA would be necessary. The specifics for needing either/or are a lot more complex than that so deep comprehension of airspace, equipment, safety, and operational regulations is mandatory. A few questions on the internet is not going to get you there.