Mobile WiFi is the making of a wireless internet hotspot from a mobile broadband connection.
Mobile WiFi is also known as MiFi.
How a mobile WiFi connection is achieved is by using a MiFi device that connects to a mobile broadband connection and then makes the connection available to other wireless devices by offering a WiFi connection.
Much as in the same way as a wireless router or wireless modem in the home works a mobile WiFi connections is done very similar but without the need for the mobile WiFi device to be plugged into anything.
For more information on how a mobile WiFi wireless device works visit our page on MiFi.