Answered by Shaykh Amjad Rasheed
Is it permitted to write on one’s copy of the Qur’an by, for example, underlining or circling a verse or writing the English translation of a word between two lines?
A. Although I haven’t seen an explicit text [h: in the books of the Shafii school] regarding this issue, it seems to me (and Allah knows best) that this is permissible especially for students, provided that it does not comprise any disrespect to the copy of the Qur’an, such as disfigurement or the erasure of a verse, in which case it would be unlawful.
And Allah knows best.
Amjad Rasheed
Amman, Jordan
(Translated by Hamza Karamali)