Housing Benefit (HB) helps people on a low income to pay their rent. You can get Housing Benefit whether you are working, or claiming other benefits, such as Income Support or Employment and Support Allowance. Universal Credit (UC) which has been recently introduced, has housing benefit included so you may have to claim this instead.
If you are affected by the “bedroom tax”, the new rule in Housing Benefit where your benefit is reduced if you have an “extra” bedroom, you may find information about Discretionary Housing Payments useful. Go to Disability Rights UK’s factsheet: Discretionary Housing Payments – your rights explained.