Goods and Services Tax Act: Primary legislation governing GST in Singapore (Cap. 117A). Covers GST registration requirements, charging requirements, tax invoice requirements, and record keeping obligations.

Income Tax Act: Singapore legislation (Cap. 134) that governs invoice documentation requirements for tax purposes and record keeping requirements.

Electronic Transactions Act: Singapore legislation (Cap. 88) covering requirements for electronic invoices and digital signature requirements.

ACRA Requirements: Accounting and Corporate Regulatory Authority requirements for business registration information and company registration number display on invoices.

Singapore Revenue Law: Requirements for tax invoice format and content, including specific elements required for GST-registered businesses.

Tax Invoice Label: Mandatory requirement to clearly display the words 'Tax Invoice' on the document.

Invoice Numbering: Requirement for progressive and sequential invoice numbering system.

Supplier Details: Mandatory inclusion of supplier's name, address, and GST registration number.

Customer Details: Requirement to include customer's name and address.

Item Description: Detailed description of goods/services, including quantity and price.

Amount Breakdown: Required breakdown of total amount payable excluding GST, GST amount, and total amount including GST.