Concepts
Three ideas come up in every e-invoice guide, and a reader who meets them for the first time halfway through a procedure has to stop and infer them. They are explained once, here, so the guides can get on with the task.
Each page answers what is this and why does it exist. None of them tells you to click anything — for that, go to the guides.
One e-invoice that reports a whole month of counter receipts under a single General Public buyer — and the RM 10,000 line it cannot cross
A pool holds a document that cannot be sent yet; a queue holds one that can. Two of the three pools never empty themselves
What LHDN actually decides, what Valid means for a document you can no longer edit, and where the 72-hour clock starts
If you are new to the whole subject, read them in that order, then go to What Malaysia Requires.
For the architecture behind them — the processors, the API calls, the PEPPOL access point — see Core Concepts.