Agile is a value-based project management process. Often misunderstood, the power of this process is only fully-engaged when upper management is totally onboard.
Often, going fully Agile requires a planned transition period from existing Waterfall processes. Coding, design, development, production and/or manufacturing often need interim solutions.
Perhaps the most familiar and comfortable process for many companies. Waterfall is still very applicable and efficient in select instances, for specific archetypal applications.