You can change your player skin in Minecraft according to the version. For the PC version, you can upload a skin to the profile page; for the Console Edition, you can choose from 16 default skins; and you can apply your own skin or buy skin packs in the Pocket Edition.
To use the profile page for the PC version of Minecraft, you need to have bought the game. You can upload a .PNG or .JPG image, and this changes the default skin.
On the Console edition, you are limited to the 16 default skins; players who use other skins are hacking and may be banned from XBox Live or the Playstation Network.
You can change the two default skins on the Pocket Edition by applying your own skin design, which uses the same formats as the PC version. You can buy the City Folk and Town Folk skin packs for $0.99 each.
Minecraft has two skin models: the original Steve and the newer Alex. They have different default appearances, and you can choose between them on the profile page for the PC version or in the settings of the Console and Pocket Editions.
Making a custom skin can be done manually by editing the default skins or by using one of the many skin editing Internet pages.