Selling digital documents, PDF files and other information products online has many advantages, including reducing costs, time savings, reaching previously inaccessible markets and environmental benefits. However, the main disadvantage is that digital documents can be easily copied, shared and pirated. If you want to sell documents online securely then the PDF file format is your only secure choice. While PDF password protection can be quickly implemented, it is also simple to remove. Selling documents securely online requires PDF DRM protection to ensure documents are locked to devices so they cannot be shared, and that use of content is tightly controlled (i.e. preventing editing, copying, printing, etc.).
Infographic Source: https://www.locklizard.com/sell-pdf-documents-securely/