Could you clarify better what you mean with "workshop"?

In a strict sense, the workshop is a Steam feature that lets games store arbitrary "stuff" on the Steam servers - in the case of Creativerse, the only workshop item that can be created is the "blueprint" - these are captured in Creativerse using Capture Blocks, then they can be uploaded to the Steam Workshop by "publishing" the blueprint.

You can read more about Blueprints in the wiki: https://creativerse.fandom.com/wiki/Blueprint

(the wiki isn't fully up to date with all the changes introduced with The Definitive Edition, but it's still accurate about Blueprints).