Glad you asked! ISO.org defines a management system as follows:
“A management system is the way in which an organization manages the inter-related parts of its business in order to achieve its objectives and to create a culture that engages in a continuous cycle of self-evaluation, correction and improvement of operations and processes through heightened employee awareness and management leadership and commitment.”
Although a management system by itself is not a software tool, it is highly recommended to use some kind of system to structure the required documents and provide an overview.
This is where Instant Management Systems comes in.