how to know company operating & not closed

How to know that xyz compay is operating and not closed (or fake)? Because many times vendors/contractors/service providers are situated vry far ; sometimes in different states and we speak or communicate only through mobile or email. It may happen that such vendor/contractor/service provider may accept advance and run away and never show up and company he presented be a fake/defunct company . In these cases which documents need to be asked before signing an agreement or which documents to be looked on ROC website? Pls guide it's a practical problem.