.What And How To Feed A 3 Week Old Kitten?

My kitty’s name is Charlie and he’s 3 weeks old. I need to know what kind of food he should be eating, how often, and what is his best type?

I have a cat who keeps vomiting her milk after she eats. She has had it every day since the 1st month but there are only 2 months left till she is done with nursing! Can you please help me! How can I make sure that this doesn’t happen again!?