Fax
Fax is like a long distance photo copier or a primitive version of email, sending a copy of a document to a different person through the phone line. You would first dial someones phone number into the fax machine and then put the document you would like to send in the fax, it will scan it and send a copy through the phone line to the recipients fax. This means they also must have a fax machine but this is the same as email.
Electronic Fax
E fax means that the recipient does not need a fax machine and the fax will be an attachment on an email. This is much easier than having to buy a fax and making sure it is always on.
Video conferencing
Video conferencing is using a webcam and a micro phone to communicate in a video to someone else anywhere in the world if they have an internet connection and a piece of software like Skype. This can also be done with just audio using a microphone but most businesses prefer to use video conferencing.