This is a bit disturbing video as a landlord's house is torn apart by a bad renter in Section 8. Your blood might boil watching this, so you have been warned.
The Housing Choice Voucher Program provides "tenant-based" rental assistance, so a tenant can move from one unit of at least minimum housing quality to another. It also allows individuals to apply their monthly voucher towards the purchase of a home, with over $17 billion going towards such purchases each year (from ncsha.org analysis).The maximum allowed voucher is $2,000 a month.
Section 8 also authorizes a variety of "project-based" rental assistance programs, under which the owner reserves some or all of the units in a building for low-income tenants, in return for a federal government guarantee to make up the difference between the tenant's contribution and the rent in the owner's contract with the government. A tenant who leaves a subsidized project will lose access to the project-based subsidy.