Written record of the Qur’an was made while Prophet Muhammad (عليه السلام) was still living. It was recited by the Prophet from memory and written down by scribes.
Scribes wrote down revelation being recited on palm leaves, leather, and bones. Each chapter (Surah) and verse (Ayat) was arranged in the order they were revealed.
The Qur’an initially was not compiled into one volume. Although some of the companions (Sahaba) of the Prophet did make personal copies for themselves after having memorized what was being recited.
Collection of copies occurred after the death of the Prophet during the caliphate of Abu Bakr (رضي الله عنه). He put Zayd bin Thabit, one of the Prophets scribes, in charge of gathering all written srolls (suhuf) in existence.
After gathering was complete all copies were then checked and verified for accuracy by companions of the Prophet. All of whom were Hafiz.
Note: “Hafiz” is an honorific title given to a person who has completely memorized the Qur’an.
After the death of Abu Bakr (رضي الله عنه) these collections were then transferred to Hazrat Ḥafsa bint Umar who was the daughter of Umar ibn Al-Khattab and one of the wives of the Prophet.
The standardization into one volume (mushaf) from those collections took place during the caliphate of Uthman bin Affan (رضي الله عنه).
Transcribing of the standardized Qur’an from said collections was done by four of the most knowledgeable scribes: Zayd bin Thabit, Abdullah bin az-Zubayr, Sa’eed bin al-Aas, and Abdur-Rahman bin al-Hisham.
After transcribing was completed copies were then sent to various territories and regions to replace any other collections in circulation. Uthman kept a copy of the standardized Qur’an in Madinah and the original scrolls (Suhuf) were returned to Hafsa.
The companions (sahabah) of the Prophet were in agreement that the standardized copy is the one true revelation that was sent down to Prophet Muhammad (عليه السلام) from Allah (سبحانه و تعالى).
The codex (Mushaf) of Uthman originally had no dots or vowel markers though. These were not necessary at the time. Most knew Arabic in a pure form. What is now known today as classical Arabic.
The spread of Islam into other countries justified the eventual need to guard against incorrect reading and pronunciation. This made the need for said dots and markers necessary.
Scholars were initially reluctant about the addition of but latter agreed that they did not change Qur’anic text or context and only aided in proper pronunciation.
Short vowel sounds were represented by dots positioned above, below, or to the left of a letter. This was introduced during the caliphate of Mu’awiyah bin Abi Sufyan by Abul-Aswad ad-Du’li.
Letters which were similar were differentiated by a different system of dots above and below during the caliphate of ‘Abdul-Malik bin Marwan. His governor al-Hajjaj appointed two scholars, Nas bin ‘Asim and Hayy bin Ya’mur, to implement this system.