The tax relief is referring to the optional deductions. The list of tax reliefs can be found at https://www.hasil.gov.my/en/individual/individual-life-cycle/how-to-declare-income/tax-reliefs/
Through the submission of Form TP1 to the employer, employees can claim tax relief. Then, the employer shall enter the deduction amount in the payroll. All the tax reliefs are preset under the Tax Relief category. All the allowable deductions are limited up to the maximum amount under the Income Tax Act 1967.
Guideline to add tax relief to payroll:
1) Payroll > Run Payroll > Select payroll month and cycle
2) Select the employee
3) Click "Add Tax Relief" > Select tax relief > Enter the amount
4) Click "Add". Tax relief item was added to the payroll.