If your employer is participating in the AIS, you need not file the income
received from this employer. Your employer will e-submit your employment income
information to IRAS by 1 Mar of each year and it will be automatically included
in your income tax assessment.
You will still have to file a tax return if you received a notification to
file. You will need to declare other sources of income (e.g. rental income, etc) in your tax return.
You can view your auto-included information in the 'Income, Deductions and
Reliefs Statement (IDRS)' at myTax Portal.