How come not two Islamic countries, sects, or even schools agree on one way to veil women?
Because the whole concept of veil is man made by men. The details of how the order to cover women came about is found in details in the hadith but what the dress code was not explained. Instead we were left with vague suggestion that “women be modest” and that got interpreted not by women but by men. So, the way women dress in Afghanistan is different to Pakistan, to Iran, to Saudi, to Egypt, to Morocco, to Sudan, to west Africa, to Lebanon and Syria. And different between Sunni, Shia, Suffi, Wahabi, living in the same country!!
The sequence of events leading to the obligation of the Hijab as laid out in the hadith are as follows:
Umar repeatedly asks Muhammad that Allah should reveal verses for the Qur’an pertaining to the veiling of women.
No such revelation is sent down.
Umar follows Muhammad’s wives one night when they go out to relieve themselves (go to the toilet) and calls out to Muhammad’s wife Sauda.
Sauda goes home in a state of embarrassment and relates to Muhammad what has happened.
Allah then reveals the hijab verse as Umar had wanted all along.
Source of the hadith and sequence are here: https://wikiislam.net/wiki/Hijab
The story of the Hijab and how it came about many years into Islam and mostly because of Umar insistence added to the many issues that negate the concept that the Quran was already written from the start of time! And, like many other verses, proves that Muhammad was being influenced into what to write in the Quran based on events around him!! Still not sure Muhammad was writing the Quran? Try reading this: