Computer programme/application for scanning schoolwork

My son has fine motor skill difficulties and at the age of 11, still writes like a 4 year old so over the last year, his occupational therapist has taught him how to touch type and he is managing well.  We now want to integrate using a computer into his everyday school life.

We are told that programmes exist where he can scan the exercise from the book or the work sheet using a mouse or ruler scanner and then it appears on screen in a format that he can just directly type onto it.

Can anyone recommend such a magical programme?  Do your kids use it and how do they find it? 

Thank you for your help Elizabeth