Every if it is ready for resource allocation.

Every operating system needs process management and it could not work effectively without process management.
The process management helps to create and delete system process: when you turn on your computer your operating system opens process to run different service and applications and some background processes will begin when the computer starts to handle various I/O processes
Suspending and resuming: process on your computer seems to be running all the time but actually it is not, it could pause for short periods of time, if a process is not executing it could be waiting for I/O or memory to accomplish a task.
Process synchronization & Process communication: A computer has a limited range of processing resources, you may think that the system is executing several process at a time but actually it is switching between them quickly so when a process is running the operating system needs a way to ensure that two processes does not access the same resources at the same time, Thus we need a good communication between process and the CPU to determine which process should be suspended or if it is ready for resource allocation.
Deadlock handling: A deadlock occurs when two processes are suspended waiting for recourses that are being used by a running process this could cause all programs to halt. The operating system use different strategies to handle it, for example: forcing a process to declare the resources it will need before it can start up.