Linking directly to PDFs from emails doesn't automatically doom deliverability, but it introduces several potential pitfalls. While some experts believe direct links are acceptable, especially when the PDF is hosted on a reputable server, the consensus leans toward caution. Key concerns include the risk of PDFs containing malware, triggering spam filters, or being blocked by mail clients. A common recommendation is to link to a webpage containing the PDF instead, which allows for better tracking, branding opportunities, and a more user-friendly experience. Furthermore, maintaining a strong sender reputation by adhering to email authentication best practices (DKIM, SPF), regularly checking link reputation, and avoiding links to suspicious sites are crucial for ensuring positive deliverability outcomes, regardless of whether you're linking to PDFs or other types of content.