Game Face is a personalised avatar generator service from EA that allows you to scan/create your face avatar and upload it to the supported EA Sports games.
Game Face is supported only by some of EA Sports titles such as FIFA, UFC, Madden NFL, NHL and NBA - Only some FIFA titles support the Game Face feature. In supported FIFA games, you can use your Game Face avatar only for the Career Mode's player.
To use the Game Face and create your personalised avatar, you need to use Game Face web-app and have an Origin account.
Game Face in FIFA
Here is the list of FIFA titles with Game Face support: