Section 8 refers to several categories of federally subsidized housing.
"Section 8" refers to the federal law that establishes the program.
Usually, you will pay a part of the rent to the landlord and the local housing authority pays the other part.
The landlord must meet federal requirements to provide the housing. You must meet requirements to be eligible and to remain in the unit.
There are also certain rights and protections provided to Section 8 participants, including in the eviction process.