Praise be to Allah.
The correct view is that it is permissible for every reader who can recite the Qur’aan well and who understands its meanings, has a sound belief, does righteous deeds and is of upright conduct to use ruqyah. It is not essential for him to have knowledge of minor matters or to have studied all branches of knowledge in depth. This is because of the story of Abu Sa’eed and the man who had been stung by a scorpion, “… and we did not know that he ever did ruqyah before that incident”, as is stated in the hadeeth.(Narrated by al-Bukhaari, 2276; Muslim, 2201). The raaqi must have a good intention and want to benefit the Muslim; he should not be concerned with money or payment, so that his reading will be more beneficial.
And Allaah knows best.