I have a template that has been created in different platform and received it through Outlook. Trying to re-create the same Email in the Salesforce Marketing Cloud Platform, but there are a lot of rubbish and table upon table in addition with some classes that are set by Outlook (MsoNormal, MsoNormalTable). Can I remove or to be exact have an HTML code base before Outlook renders it, so I can modify it in Marketing Cloud?
Yes, you can 'View Source' to see what it was, as long as it hasn't been forwarded or replied to in the mean time. Go to the original, and open it in its own window (double click), then go to the Move tab, click "More move actions", then "Other actions", then View Source.
Alternatively, go to the bottom of the email and somewhere right at the bottom you can right click and a 'View Source' option will show. It might be on the side - somewhere without content.
You may also be able to use the 'click here to view it in a web browser' and go from there - not sure about that technique, whether it shows the before or after. I think it's the MS'ified code, actually.