Check IRAS first.
I am not too sure about your question, but can provide you some info below,
1) Check whether your company participated in the Inland Revenue Authority of Singapore (IRAS) Auto-Inclusion Scheme. That scheme will help all of employees to do e-filing for employment income to IRAS. That means if your company participated the scheme, company will help you to file your income tax return. what you need to do is login toIRAS website
.
2) You are required to file your income tax return either by e-filing or paper way as long as an income tax return/ IRAS Pin mailer has been issued to you.
3) Remind: The closing date for e-filing and paper returns is 15 April 07.
Hope it help. If any incorrect information given, pls update.