Answered: How can I remove this code, please?

That is not part of Q2A. It seems to be part of the content that you are pasting in the CKEditor. I guess you're copying content from Word, another site or another tool and pasting with the format.

If you want the HTML to be cleaner, you will need to paste without the format (which can be done with CTRL+SHIFT+V) and format the content using the CKEditor.