A lot of job ads for pastry chef mentioned "requires 2nd year or final
year apprentice chef", is that mean after a person finishes their TAFE
studies, they have to be someone's apprentice before becoming a pastry
chef? If such is necessary, how many years does one have to be an
apprentice usually?

So the career path goes like:
N years in TAFE
X years as apprentice
Full Pastry Chef
?