Does sharing code on Arduino Create automatically grant any license rights? I have code I am happy to share under a GNU GPL License and which is marked accordingly. Before I upload it to Arduino Create Web Editor I want to check whether in doing so I inadvertently grant additional license rights. I have searched for any terms and conditions which may inform me but not found any as yet.
Arduino Create doesn't assume any licensing of any form. Sharing isn't a public thing. You have to specifically provide someone with a link to your sketch. If you choose to post that link publicly then that is your concern.

Any licensing should be included with your sketch.