The Software Requirement Specification, also known as the SRS Document, is one of the most important documents for the development team. It is a full explanation of how a system will work when it is built. It outlines what needs to be done to meet the business requirements. It includes all of the system's properties, business requirements, constraints, and behaviors, like how fast it responds, how reliable it is, how much space it needs, etc. So, it's also used to estimate how much money and time will be needed to make that software.