This command is a simple avatar creator,
how to make it work,
1. put down a command block and put in this command: /tp @e[type=ArmorStand] @p
then put it on a super fast clock like this:
then get a player head (/give Username minecraft:skull 1 3 {SkullOwner:Username})
get armor (no helmet)
and a wepon (item)
right click using the things told and you got a custom advitar!