When I was looking for a reliable fax app for sending legal documents securely, I found that eFax is one of the top choices. It offers robust security features, including encryption, and allows you to send large files up to 3 GB, which is perfect for legal documents. Another great option is FAX App, which is HIPAA compliant, making it ideal for legal and medical documents. If you're interested in exploring more options, I recommend checking out this detailed review https://www.guru99.com/best-fax-apps-for-mobile-phone-and-desktop.html . Both apps are user-friendly and offer cloud storage for future access.