Avatars were introduced in Hattrick in the Redesign 2008. The avatar is a fictional representation of the manager of the club. Immediately after its release, many managers argued that there were no female avatars, so they were also introduced a few weeks later. In the supporter update on the 17th of March 2009, presented in this editorial, managers were given the possibility to alter their avatars.
An avatar can be chosen by using the link on the manager page.
Avatars are randomly generated. It is not possible to "make" one yourself, if you not pleased with the one you got generate another.. over and over again.