Answer:
See below.
Step-by-step explanation:
It was your typical pre-industrial arrangement.
At the top, the Huēy tlahtoāni, The Great Speaker: he was called that because he was the most important among the three rulers of the Triple Alliance (usually misnamed the ‘Aztec Empire’), and thus the first when it came to ‘speak’.
Then, the Pīpiltin, the land-owning aristocracy, from where the high priests and military leaders were recruited.
The Pochtecas, who were the commercial caste, in charge of the commercial network and appears they were in charge of gathering intelligence about neighboring peoples.
The Macehualtin, commoners in charge of the agriculture and artisan work, they carried the dual weights of taxes and military service; but at least were in a better position than the Tlatlacotin.
These are usually described as slaves, but they were more properly an indentured class: they were either sons or daughters of commoners sold to pay debts, or commoners who sold themselves into slavery, or prisoners of war.
But, and this is a big but, they were not actual property: they had contracts that established their duties, and could buy their way out of the contract. Also, they could have personal property, and even own land.
And their condition was not hereditary: their children were free, so they were not required to pay off their parents' debt.