Depends on which courier you are using

If it's the country's national courier then poslaju will be in charge of delivering the goods to you.

1) You'll receive a letter to appoint poslaju to pay the duty tax, fee i am not sure.. Maybe rm50?

2) Or you head to customs yourself and make the payment at klia2 poslaju.

If it's DHL/FEDEX etc, they'll inform you about the duty before it even reaches Malaysia and you'll have to make the payment to them.. Hassle free and convenient.. Alot faster than our national courier