What is needed for APRS?

What precisely are the necessary requirements or prerequisites for someone to effectively engage with and utilize APRS? Are there any specific skills, knowledge bases, or technical proficiencies that an individual should possess in order to navigate and take advantage of all that APRS has to offer? Understanding the foundational elements that form the cornerstone of APRS usage can undoubtedly empower users to maximize their experiences and capitalize on the opportunities presented by this platform. So, what exactly are the CORE necessities for APRS?