How does cinnamon grow is it a root flower or leaf?

None of the above. Cinnamon is a bark of a tree (shoot).

Cinnamon trees only grow in very tropical climates. Cinnamon is harvested by growing the tree for two years then coppicing it. The next year, about a dozen shoots will form from the roots.

The branches harvested this way are processed by scraping off the outer bark, then beating the branch evenly with a hammer to loosen the inner bark. The inner bark is then prised out in long rolls. Only the thin (0.5 mm (0.020 in)) inner bark is used; the outer, woody portion is discarded, leaving metre-long cinnamon strips that curl into rolls ("quills") on drying. Once dry, the bark is cut into 2.0-3.9 in lengths for sale.