All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.
The compilation, dotting and vocalization of the Mus-haf are not considered religious innovations, because a religious innovation is something that the Prophet, sallallaahu ‘alayhi wa sallam, did not do, despite a need and ability to do it during his lifetime.
There was no need for dotting or vocalization of the Mus-haf during the lifetime of the Prophet, sallallaahu ‘alayhi wa sallam, because the majority of companions were illiterate and depended on memorization, also because there was no danger of an inaccurate reading of the Quran. However, when Islamic conquests extended to many countries and non-Arabs began to embrace Islam, dotting and vocalization of the Mus-haf became necessary.
Indeed this act may be referred to as innovation only from a linguistic perspective, just as when ‘Umar described the prayer of At-Taraaweeh as a good innovation. Innovating an act of worship that the Prophet, sallallaahu ‘alayhi wa sallam, did not perform, despite the need and ability to do it during his lifetime, is considered a religious innovation (which is absolutely prohibited).
We mentioned the ruling on dividing religious innovations into that which is good and bad in the following Fataawa: 2741, 91407 and 17613.
Allaah Knows best.