Whether you're a student or a member of staff the process you will need to use is dependent on who the person is that you're reporting.
If you want to make a formal report about a staff members conduct you can start by making an advisor request through Report + Support, or contacting your HR Business Partner directly.
If you want to make a formal report about a student's conduct you will need to contact the student casework team.
The below guides offer more detailed information about the formal reporting process should you wish to find out more before making a report.