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/

Reference: https://www.knowledgehut.com/tutorials/itil4-tutorial/itil-management-practices-processes