I need some help regarding hair fall I have been...

 ?What is the treament of hair loss
You have to start the treatment by following some instructions for example : you have to avoid using hair drying machines so much , and avoid using hair dyes , it's important to drink as much water as you can , you will be prescribed to use Minoxidil or Finastride , or if there was no response : hair transplantion or laser therapy .you also have to treat chronic . disease such as anemia , and you also have to avoid anxiety
?What is the investigation should be done
there is no need for any test , just CBC if anemia is suspected 
?What are the causes of hair loss  

• • Dryness
  • Family history
  • genetic factors
  • Poor nutritinal state

Advice :
follow the previous instructions