How to search more fields using single text field textbox
It's Global: Combine fields filter.

Follow Up:-

process No 1:-


  Add fields to filter criteria
  
  Add Global: Combine fields filter to filter criteria
  
  Check fields you want to combine in filter's settings


Process No 2:-


  Add Fields 
  
  Install  Views filters populate module.
  
  Add Global:Populate filters  to filter criteria
  
  Check fields you want to combine in filter's settings


I think this answers are resolved your problem.