The original avatar refers to the avatar created by the user himself, and the watermark refers to adding logo symbols or words to the avatar to prove that the creative right of the avatar belongs to the user himself. Signature id usually refers to the unique identifier registered by a user on a certain platform, which can be the user's username, nickname or other specific combination of numbers and letters.
On social media, online forums, blogs and other platforms, many users will use original avatars to show their personality or represent their own brands or enterprises. In order to protect their original avatars from being stolen or abused, users can choose to add their signature id or other identification symbols to their avatars to show their ownership of their avatar creation rights.