You can automate service request approvals by creating a workflow using the Workflow Automator. Let’s assume a scenario where you must send a service request for an Apple Macbook to the requester’s approval manager and the department head whenever you get a service request. The service request will be sent to the fulfillment team only after approval from both managers. 

Also, refer to the article below for further reference:

https://support.freshservice.com/support/solutions/articles/211198-setting-hierarchical-approvals-for-service-requests-using-workflow-automator-