On every night of Ramadan, it is recommended to perform an optional prayer after the ^Isha’ prayer. It is called the Qiyam of Ramadan prayer. Some call it also the Tarawih prayer. The Messenger of Allah ﷺ said:
“صلاةُ اللَّيلِ مَثنَى مَثنَى. فإذا خَشِىَ أَحدُكمُ الصُّبحَ فَلْيُوتِرْ بِركعةٍ.” رواه البخارىّ ومسلم.
It means: The prayer at night is (preferably) two rak^ahs at a time. If one fears the dawn will break, let one pray one rak^ah of Witr (al-Bukhariyy, Muslim). The Messenger of Allah ﷺ also said:
“أَوْتِرُوا بِخَمسٍ أو بِسبعٍ أو بتِسعٍ أو بإحدَى عشْرةَ أو بأكثرَ من ذلك.” رواه ابن حِبَّان وابنُ المنذر والحاكم عن أبى هريرة.
It means: Pray the Witr after praying five, seven, nine, eleven, or more rak^ahs (Ibn Hibban, Ibnul-Mundhir, al-Hakim).
These two hadiths signify that the Muslim may pray after ^Isha’ as many rak^ahs as desired, without specifying a maximum number. Lady ^A’ishah, may Allah raise her rank, said:
“ما زادَ رسولُ الله ﷺ فى صلاة الليل فى رمضانَ ولا فى غيرِه علَى إحدَى عشْرةَ ركعة.” رواه البخارىّ
It means: The Messenger of Allah did not pray at night more than eleven rak^ahs in Ramadan or otherwise.This hadith only tells what Lady A’ishah witnessed the Prophet ﷺ do. It does not mean that one cannot pray more than eleven rak^ahs. This is substantiated by the hadith of Imam ^Aliyy narrated by Hafidh al-Khila^iyy that the Prophet ﷺ prayed sixteen rak^ahs at night. Hafidh al-^Iraqiyy said that its chain is good.
It became conventional among many to label the twenty rak^ahs followed by the three Witr rak^ahs the Tarawih prayer. As for the Qiyam of Ramadan, Imam ash-Shafi^iyy said: “There is no limit for the number of rak^ahs the Qiyam of Ramadan prayer has.” Hence, let the intention in the heart be: “I now pray the Qiyam of Ramadan prayer.” It is also good to pray it in congregation. The practice in Islamic countries is to recite the thirty Juz’s of the Qur’an in the congregational Qiyam of Ramadan prayer, at the rate of one Juz’ every night.