A service request is defined as a request from a user or a user's authorized representative that initiates a service action which has been agreed as a normal part of service delivery.

The purpose of the service request management practice is to support the agreed quality of a service by handling all pre-defined, user-initiated service requests in an effective and user-friendly manner. Service request management is dependent upon well-designed processes and procedures, which are operationalized through tracking and automation tools to maximize the efficiency of the practice. To be handled optimally, service request management should follow these guidelines:

Service requests and their fulfilment should be standardized and automated to the greatest degree possible.

Policies should define which service requests will be fulfilled with limited or even no additional approvals so that fulfilment can be streamlined.

The expectations of users regarding fulfilment times and costs should be clearly set, based on what the organization can realistically deliver.

Opportunities for improvement should be identified and implemented to produce faster fulfilment times and take advantage of automation.

https://www.bmc.com/blogs/itil-service-request-management/