This Guide presents a range of possible solutions to support the digital transformation of invoices for international trade. These solutions span a spectrum: at one end, e-invoices are still exchanged in PDF format via email, while at the other, advanced systems enable real-time electronic data exchange between trading partners. Between these two ends of the spectrum, hybrid approaches can involve partial digitalization of trade processes. The Guide is intended to support the parties to the Framework Agreement on Facilitation of Cross-border Paperless Trade in Asia and the Pacific (CPTA) to identify national initiatives and explore opportunities for collaborative pilot projects. While the discussion is relevant to most countries globally, certain sections are tailored specifically to the needs and context of CPTA parties.