For USCIS, you can use any combination of the names on the marriage certificate. You can't shorten the spelling of names. For example, Mary Smith married John Doe. She can use Mary Smith, Mary Doe, Mary Smith Doe, or Mary-Smith-Doe as her new, legal name .
Otherwise, I would wait until naturalization to become a US citizen to make the name change.
You can use new legal name on all USCIS paperwork.....and everywhere else.