Fax document (Efax Reader)
EFX is a file extension for a document file used with eFax messenger software. EFX stands for EFaX. EFX files contain a fax document that can be sent and received by email, desktop application, and a web interface.
EFX files can be opened by eFax messenger software. EFX files can also be sent if using the paid version of eFax messenger software.
MIME type: image/efax
Learn more about .EFX files:
Visit eFax web page.
Read more about Faxing at ITKnowledgeExchange.com.