The armour stand editor is a cosmetic feature that allows users to very intricately modify armour stands to create detailed scenes and/or decorations. To see a full list of editable components please read the wiki here.
Though this is a sponsor perk, there are still rules and restrictions you must follow when using the feature. Breaching any of these may result in punishments - including removal of the perk entirely. There are no refunds so ensure you understand these before buying.