The word "wuz" that you have written is not correct, and does not exist.
The correct way to write it is "what's up?" (contraction) or "what is up?"
It is a slang greeting used mainly in the US.
You may be aware of a very popular smartphone app called "Watsapp".
This is a wordplay. It combines the word "app" with the expression "what's up?"
In the US, it is used in a way that it implies "what are you doing?" or "what is new in your life?" or "what's your latest news?" or "what is going on?"
However, in the UK, it means "what is the matter? Why are you sad / upset?"