Newbie questions

Hello all, I just started doing FBA and am currently sourcing my first product. Before I go out to buy anything, I have a few questions first…

when sourcing non name-brand items from wholesalers like alibaba, this will require me to add the product as “a product not sold on amazon”, correct?

also when sourcing from china, do i need to receive the physical product first and scan the items in on my end and then ship them to amazon? or do i just need to buy the UPC online and then i can have the items shipped directly from supplier to amazon?

thank you for your time.