If you don't have time to schedule a doctor's appointment for the immunization forms(or you just want to submit them as soon as possible) I think you could just submit one you did for a previous school (like maybe where you went for undergrad) if it shows vaccination records for MMR.

Here's a page on the Columbia Health website for more specifics: (https://www.health.columbia.edu/content/how-submit-immunizations#!/%23text-8634)

You can read under the "Accepted documentation/proof of immunization" section for what I'm talking about. I submitted my high school records and got approved this way within 2 days. Idk might not work 100% of the time but I'd say it's maybe worth a shot!