Turbotax software says: "Your MULTI was uploaded successfully!" when I uploaded a document. There is also a button that says "This isnt a MULTI" what does MULTI mean??

What document did you upload from where?  A 1099?  For what?  

@trev851075 I am also looking for the answer to this question. Looking online or using the Intuit Assist, I get nothing that would help me what "MULTI" means.

Did you figure it out?