What is the wudu in islam? What are the types of wudu in islam? How many types of wudu are there?
Ablutions are divided into three types according to their degree of necessity:
1) Fard (Obligatory) Wudu:
According to all schools of law, performing the wuḍū becomes obligatory in two cases:
a) If a person is not in the state of wuḍū it becomes obligatory for that person when he/she is going to perform the ritual prayer (ṣalah). Whether this prayer is an obligatory, wājib, or supererogatory prayer, whether it is not a complete prayer as in the case of funeral prayer or the prostration of recitation, the same ruling applies. The basis of this ruling is the Qur’anic verse on wuḍū and the hadith in which the Prophet said, “When I am going to pray, I have been commanded to perform the wuḍū.”
b) It is necessary to be in the state of wuḍū to touch the Qur’an. Whether it is a piece of paper, leather, a wall, or a coin wherein a verse is written, it is subject to the same provision in terms of touching it. The basis of this ruling is the verse “That this is indeed a Qur’an Most Honorable, … Which none shall touch but those who are clean”  as well as the Prophet’s saying “Only those who are thoroughly cleansed can touch it.”
2) Wajib (Necessary) Wudu:
According to the Ḥanafis, in order to circumambulate the Ka’ba the ablution by a Muslim who is not in the state of wuḍū is wājib (necessary) whilst the majority of jurists regard this type of wuḍū as farḍ (obligatory). The evidence for this ruling by the majority of jurists is the following hadith: “The circumambulation of the House of Allah is a ritual prayer. The difference is that Allah has made it permissible to speak during the circumambulation. Whoever speaks in circumambulation should only speak good things.” The Ḥanafis, on the other hand, do not consider tawaf as an actual ritual prayer. Therefore, they believe its validity does not depend on being in the state of wuḍū. Yet, they argue that those who circumambulate the Ka’ba without being in the state of wuḍū are required to offer a sacrifice since they are abandoning a wājib act.
3) Mandub Wudu:
This is the type of ablution that is carried out for the sake of being constantly in the state of wuḍū in order to recite the Qur’an by heart (without touching the text), to recite the adhān and iqāmah, to touch the books written within the Islamic sciences, to read and teach Islamic sciences, to wash the body for a funeral or to attend a funeral ceremony (not funeral prayer), or to simply achieve serenity. With a wuḍū performed with such an intention, any kind of prayer can be performed and the Qur’an can be read whenever required.
On the other hand, it is considered makrūḥ for a person, who is in the state of wuḍū, to perform the wuḍū again without performing any prayer, since it is considered a waste of water. Moreover, it is not permissible to perform the wuḍū with stolen water or with water belonging to an orphan.
 Al-Mā’ida, 5: 6. See Abū Dawūd, Aṭ’ima, 11; al-Tirmidhī, Aṭ’ima, 40; al-Nasā’ī, Ṭaḥāra, 100; Aḥmad ibn Ḥanbal, I, 359; al-Darimī, Wuḍū’, 65. Al-Wāqi’a, 56: 77-79. Malik, Muwaṭṭā’, Qur’ān, 1; al-Qurṭubī, Jāmīʿ, XVII, 146; al-Shawkanī, Nayl al-Awṭār, I, 205. Al-Zaylaī, Naṣb al-Rāya, III, 57. Al-Zuhaylī, ibid, I. 210-212. Ibn Abidīn, Radd al-Mukhtār, I, 111.