Wha was the purpose of the northwest ordinance? Plz help

To prevent the spread of slavery.

The land allocated in the Northwest Ordinance of 1787 was the first official territory of the United States. Guidelines were set up for creating states out of the territory, including how aspiring states could claim/divide up the land and how governments were to be formed.
The Northwest Ordinance also established some guarantees of natural rights that were eventually adopted into the Bill of Rights. Protections offreedom of religion, habeus corpus, and fair punishments were included for the land decreed by the Northwest Ordinance.
Slavery was made illegal in the territory by the Northwest Ordinance. This is especially important because it made northern states free of slavery, which eventually increased tensions between the north and the south, contributing to the Civil War. Hope this helps!