Explanations

Pay attention to the pronunciation of WHAT'S YOUR NAME? It is usually pronounced like "watcha name?"

WHERE ARE YOU FROM? - at the end of the sentence FROM is usually pronounced with the vowel in SOCK
I'M FROM FRANCE- in the middle of the sentence it is pronounced with a SCHWA, very weak

TORONTO- he pronounces it "torono", because in AmE, when the T goes after an N it may disappear
MANHATTAN- listen carefully to the pronunciation of the T here. She pronounces it in the back or her throat, rather than with the tip of her tongue. That often happens when we have an N after the T (in the syllable -TAN, the A is pronounced with a SCHWA, so weak that it has disappeared and we are left with -TN)
WHAT IS YOUR NAME?- another different T. When a T goes between vowels, like here, it is usually pronounced like the /R/ in the Spanish "cara". That may happen in BrE, but it always happens in AmE

HI! HOW YA DOING?- This is a very common greeting, especially in AmE. It is a relaxed pronunciation of "how are you doing?", and it means "how are you?"