Hi @LisaEiden-Dillo,
As far as I know, neither the Canvas RCE nor Canvas Studio currently offer the ability to blue or replace the background. I'm not sure if your post was a question or if it was meant to be a feature request. if you meant to request that such a feature be added to Canvas or Canvas studio, you can submit that request to the ideas area of the community.
Hope this helps a bit!
-Chris
