Tenant screening services come in many "shapes" and "flavors". Landlords can call in the request or find an online service. Many services offer much more than just a credit report. The basic service would include a credit report and maybe an eviction report.
The most complete tenant background check would include the credit report, eviction report, possibly a criminal report, and would verify the applicants current job and their residency history. Spending a little extra on tenant screening services is well worth the minimal extra cost.