Personal Income Tax 2019 : Malaysia Taxpayer’s Responsibilities

Other than truthfully declaring your income and reliefs, and submitting your tax files before the deadline stipulated by LHDN, taxpayers are also responsible for record keeping.
Taxpayers are required to keep the following documents for seven years from the end of the year in which the Income Tax Return Form (ITRF) is filed:
EA/EC Form
Original dividend vouchers
Insurance premium receipts
Books purchase receipts
Medical receipts
Donation receipts
Zakat receipts
Children’s birth certificates
Marriage certificate
Other supporting documents
Working sheets (if any)

This is extremely important as LHDN has the right to request for any supporting documents for taxes paid previously. So if you’re filing for reliefs, make sure you keep your documents!
Failure to produce the supporting documents during a tax audit can result in tax penalty of RM300 to RM10,000, or imprisonment, or both!
credit to The Definitive Guide To Personal Income Tax In Malaysia For 2019, iMoney earning Centre