Humanity began with the creation of the first human being, Prophet Adam (AS). After humanity was established on this earth Allah (SWT) appointed righteous people from among the people to guide the masses to the oneness and divinity of Allah (SWT) and these righteous people were the Prophets who all bore the same single message that there is no God but Allah (SWT). Some of these prophets were given sacred scriptures. Out of these were the Torah given to prophet Moses (AS), the Psalms given to prophetDavid (AS), the Bible given to prophet Jesus (AS) and the last and greatest of the texts were revealed to the final messenger of Allah (SWT), Prophet Muhammad (SAW). The previous textures were sent and meant as guidance to a specific nation and these all eventually became corrupted my man’s hand after the prophets had passed away. The Quran is the exception among all the others for a number of reasons, the first being that Allah (SWT) has Himself taken up the guardianship of the Quran and it will remain in its true form for all of eternity. The second reason is that Prophet Muhammad (SAW) was sent as a prophet to all of humanity and the religion of Islam is destined become the only religion in the world.
One of the ways that the scholars have reached consensus on about how the Quran has remained unchanged is due to the existence of the Hafiz, the people who memorize the entire Quran. These are done usually in institutes or mosques but in the age of the internet, people have now the opportunity to memorize Quran online. Online Quran memorization classes that are provided by online schools are similar in execution as regular classes and are in some cases superior than attending a regular center. People who memorize Quran online can do so at their own pace and according to their own schedule which makes attending online Quran memorization classes very convenient for those who have busy lives and do not find the time to go to mosques and centers to perform this task.