Selling through WhatsApp in Malaysia looks simple until you hit tax and audit requirements. A customer sees your product in a chat message, clicks 'buy', you send a receipt—and you've just created a compliance audit trail that Revenue Board (LHDN) expects to match your SST return. Miss one piece, and you're not just exposed on the transaction; you've fractured your entire tax file. The good news: the boundary between chat and formal invoice is clear, but only if you know where it runs. SST registration is your first gate Before you sell anything on WhatsApp in Malaysia, you need to register for Service and Sales Tax (SST). This is not optional. LHDN treats WhatsApp sales the same as in-store sales—you must have a valid SST registration number, and it must appear on your invoice. The rule is straightforward: if your annual turnover exceeds RM500,000, registration is mandatory. Below that threshold, registration is voluntary but recommended if you have any B2B customers (they often require it). Once registered, you are legally required to issue a proper invoice for every sale, regardless of whether the customer is an individual or a business. This is where many SMBs stumble. They treat WhatsApp as casual—a quick back-and-forth, a Stripe payment link, maybe a screenshot of the receipt. LHDN disagrees. From their perspective, you made a supply of goods or services, collected money, and must prove it with a compliant invoice. No exceptions for channel. What must live in the invoice, not the chat Your WhatsApp conversation can contain product descriptions, negotiation, and payment links. But the legally binding invoice—the document LHDN audits—must include these elements: Your SST registration number (mandatory, top-right corner is standard) Invoice date (the date you issue the invoice, not the chat date) Invoice number (sequential, unique, auditable) Customer name and tax ID (if they provide one; if B2B, their SST number must appear) Itemized supply description (what they bought, not 'stuff' or 'project') Price before SST (the supply value) SST amount (6% of the supply value, labeled separately) Total due (supply + SST) Your business name, address, and contact details Payment method and date received (optional but smart: 'Paid 15 Nov 2024 via bank transfer') If your invoice is missing the SST number, the customer's tax ID, or the itemized breakdown, LHDN will flag it as non-compliant. You'll owe the SST, plus penalties, even if you collected it from the customer and sent it to LHDN on time. Do not rely on a WhatsApp message, email receipt, or Stripe invoice. Generate a formal, numbered invoice every time. Collecting the customer's tax ID in chat—but verifying it first If your customer is a business, you need their SST registration number before you issue the invoice. This is often where things go sideways: customers give you a number, you invoice it, and later LHDN tells you it doesn't exist or belongs to someone else. The smart workflow: Ask for the tax ID in WhatsApp (e.g., 'For invoicing, please share your SST registration number') Validate it in real time (or at least before you generate the invoice). LHDN maintains a registry; you can check via their online portal or ask your accountant to confirm Store it in your CRM with the customer record, so you don't ask again next time Reference it on the invoice If the customer refuses to provide a tax ID or gives you a bogus one, you can still invoice them—but you invoice them as an individual consumer, not a business. Your invoice then shows their name (not a business name) and no tax ID field. You're still liable for the SST, but at least you have a defensible position if LHDN audits you. Building the audit trail: what WhatsApp captures and what it doesn't LHDN audits happen. They will ask for: Proof that the sale occurred (WhatsApp chat, email, order record) The invoice you issued Proof of payment (bank statement, receipt, payment gateway record) Your SST return, showing the transaction recorded WhatsApp messages are admissible evidence in Malaysia, but they're not a substitute for invoices. Here's what you should be saving: WhatsApp conversation (screenshot or export) showing the agreement and customer identity The formal invoice (PDF, with your SST number, sequential number, and all required fields) Payment proof (bank transfer receipt, payment gateway confirmation email, or screenshot of cleared funds) Customer tax ID (if B2B; store this in your CRM or accounting system alongside the invoice) Do not delete WhatsApp chats. If LHDN asks, you must be able to show the conversation. Many SMBs archive chats instead of deleting them—do that. Also export invoices as PDFs, not just keep them in your accounting software; if the software fails or you switch, you still have paper trail. Invoicing tools that play well with Malaysian tax rules You can issue invoices manually (Word template, PDF), but the moment you hit 10+ sales a month, you need a system. Here's the reali