Timesheet Approvals
Timesheets capture information about work over a period of time - typically a pay period. After they are filled out, timesheets can be submitted, reviewed, and then approved or rejected.
Only people with Jira Administrate permission can become approvers. You can make people such by changing their role to Site Administrator or Trusted Users.
Or on the latest JIRA version make the corresponding user be part of the Jira administration product.
Example:
If you are a Reviewer, you can use the approval page to either approve or reject timesheets submitted to you.
You can manage timesheet approvals for your team by viewing the timesheets of your team members and to review also past actions