Is it permissible to read the Quran from a computer screen instead of the Mushaf to avoid closing the Mushaf when someone enters?

It is permissible to read the Qur’an from a computer, but one must not prioritize supererogatory acts over obligatory ones. If reading the Qur’an will distract you from performing your work duties as required, then you must stop reading and postpone it until after you have finished your work. However, if reading does not distract you from performing your work, then there is no harm in it.