I am expecting a flat package in a bubble mailer. I am aware that if the package is too big, the postman will ring the doorbell and get you to collect it, or if you are not home, he will leave you a card and you will have to go to the post office to collect it. However, the package I am expecting is rather small and flat, and can fit into the mailbox. Will it be dropped into the mailbox instead?

I believe if parcel/package, they will knock the door or leave a card for you.

But it is flat enough to fit in the mailbox. Will it go directly into the mailbox instead?

nope.. they won't do it except pos express only,
other then that , they need your signature / ic no. to collect the staff. this is their rules

How is your package being delivered to you, as in, would you need to sign for it?

If you don't need to sign for it, then the postman will either drop it into your mailbox/throw it into your house/leave it on your gate/leave it somewhere at your place
If you need to sign for it, the postman will leave a notification card and you'll either have to collect it at the stated location, or if you're using Pos Laju, you can call 1-300-300-300 or email them at csc@pos.com.my to arrange for a second delivery FOC

I don't think I need to sign for it - it is sent via the cheapest airmail option from Australia, so yeah...

Thanks for replying!