The Housing Authority does not screen tenants for you. You must do this yourself, just as you would screen non-assisted tenants. You should ask for Social Security number, references, current and previous landlords, credit history, employment history, criminal record, etc., and check the information carefully.
WHA will tell you the number of people on the voucher, current and previous address, and current and previous landlord. WHA’s concern is checking that the applicant meets the income limits and other Section 8 HCV eligibility requirements. Screening the tenant is the landlord’s responsibility.