There are types of POS systems for different business types and industries, and different hardware and tech configurations within each industry POS. For example, retailers, restaurants, cafes, and salons all need different functionality within their POS systems, so there is POS software designed for each.
You can also opt for POS apps and other mobile POS systems, a touch-screen vs desktop system, whether your POS is cloud-based, locally stored, or hybrid, and whether or not it is open-sourced. Most popular POS systems are cloud-based and can operate on a variety of mobile, touch-screen hardware, and sometimes desktop computers.