The tea leaves when plucked, often by hand and at times by machine, are taken to the factory where the manufacturing process begins. This would begin the process of withering followed by fermentation which then leads to the leaves being put into the dryer and then sorted to different grades.
As far as hand-rolled tea is concerned, the leaves that are plucked are taken to the factory but there are none of the above processes that take place. The leaves are spread into a thin layer to allow it to wither (to reduce the moisture content in the fresh leaf). Each leaf & a bud or two leaves and a bud is then rolled by women, gently in the palms of their hand to create Teas such a Pearls, Needle Tea.