Is it permissible for someone who does not have an ijazah or has not studied under sheikhs to teach the Qur’an with tajweed and memorization?

It is a prerequisite for anyone who teaches the Quran to have received it orally from scholars, and it is not permissible for someone who has not received it in this manner to teach it. This is because the Mushaf contains letters that are not pronounced and letters that have been omitted, in addition to the proper way of pronunciation and the articulation of letters from their correct points of articulation with their respective qualities. This is based on the Almighty's saying: ﴿So when We recite it, then follow its recitation﴾ [Quran 75:18], and based on the saying of the Salaf: "Do not take the Quran from one who only learns from the Mushaf." As for teaching a Muslim what one knows well from the Quran and Sunnah, it is permissible, based on the Prophet's (peace be upon him) saying: "Convey from me, even if it is a single verse," and "The best among you is he who learns the Quran and teaches it."