How can you detect whether an app changes device output? Can additional users preserve OS stability and usefulness? Can the OS's stability and usefulness expand with users?

I need help answering these questions on the application JAMF ( apple device manager application)    A0.4 Resources for this implementation: What kinds of resource or budget constraints were specified up front at the beginning of the effort to implement the system?A0.5 Addressing failure or setbacks: If the team could not complete its work on developing or implementing the application in a given week, did the IT staff alter the way they approached the work or did they work overtime (or ask for more resources)?A0.6 Turnover of staff: How much turnover of IT staff was there during the course of the application implementation? How much among the business users / stakeholders?

Out of all the things an OS can do, what are the three primary ways in which it may interact with its users?

Changing between apps is possible thanks to multitasking. Is it feasible to alter the operating system on a personal computer? Is it? If that's the case, what comes after that?