Question Summary:
Reading ‘bismillah hirahman nirahim’ , 786 times, then blowing on water and drinking

Question Detail:

What is the validity for the following wazeefa, it has been prescribed and is known particularly for studies; Reading 'bismillah hirahman nirahim' , 786 times, then blowing on water and drinking that. 

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.  
 
Assalāmu ῾alaykum wa Rahmatullāhi Wabarakātu
 
 
There are many wazeefas that are not mentioned in the Quran and Ahadith.They are tried and tested and found to be useful. 
According to Shariah , there is no prohibition in practising on something that is tried and tested.
Practising on such wazeefas is mubaah(permissible) on condition, the words of the wazeefas are not against our beliefs and one does not regard such wazeefas  to be compulsory. If one regards such wazeefas to be compulsory,then such wazeefas will be bidah.
The enquired wazeefa is probably tried and tested. It is permissible to practise on that. However, we should practise on the duas of the Quran and Ahadith. The duas shown to us by Allah and his Rasul are more effective. No wazeefa can be equivalent to the duas of the Quran and Ahadith.  
 
 
 
 
And Allāh Ta῾āla Knows Best
 
Jibran Kadarkhan
Student Dārul Iftā
Mauritius
Checked and Approved by:
Mufti Ebrahim Desai