What Are the Conditions of Tawaf?
Question

What are the conditions and obligatory parts of tawaf?
Praise be to Allah.Conditions of Tawaf
The scholars have mentioned a number of conditions for tawaf or circumambulation of the Ka`bah to be valid. 
They are as follows:

Being Muslim

This is according to scholarly consensus. Tawaf done by a disbeliever is not valid, because tawaf is an act of worship, and acts of worship are not valid and are not acceptable if done by a disbeliever.

Being of sound mind

This is the view of the Hanafis and Hanbalis. The Malikis and Shafi`is did not stipulate that, by analogy with the fact that tawaf done by a minor who has not reached the age of discernment is valid, if his guardian forms the intention (niyyah) on his behalf.

Forming the intention (niyyah)

There is consensus among the scholars on this point, because the Prophet (blessings and peace of Allah be upon him) said: “Actions are but by intentions, and each person will have but that which he intended.” (Narrated by al-Bukhari (1) and Muslim (1907)

Covering the `awrah

If a person circumambulates the Ka`bah naked, then his tawaf is not valid, because the Prophet (blessings and peace of Allah be upon him) ordered that it be proclaimed during the Hajj: “No mushrik should perform Hajj after this year [i.e., 9 AH], and no one should circumambulate the House naked.” (Narrated by al-Bukhari (369) and Muslim (1347)
Shaykh Ibn ‘Uthaymin said: “If a person circumambulates the Ka`bah naked, it is not valid, because it is a kind of tawaf that is forbidden, and the Prophet (blessings and peace of Allah be upon him) said: “Whoever does an action that is not part of this matter  of ours [i.e., Islam], it will be rejected.” (Ash-Sharh al-Mumti‘) (7/257).

Being in a state of purity

We have discussed this condition in detail in the answer to question no. 34695 .

One’s clothes and body should also be clean and free of impurities according to the majority of scholars.

We have discussed the difference of opinion concerning that in the answer to question no. 136742 .

Performing seven complete circuits

If even one step is missing from the seven, then tawaf is not complete.
An-Nawawi said: 
“One of the conditions of tawaf is that it should be seven circuits, each one starting and ending at the Black Stone. If one step is omitted from the seven, then one’s tawaf does not count, regardless of whether one remains in Makkah or has left to return to one’s homeland, and that cannot be made up for by offering a sacrifice or doing any other act.” (Al-Majmu‘, 8/21)

Keeping the Ka`bah on one’s left.

That is because the Prophet (blessings and peace of Allah be upon him) kept the Ka`bah on his left, and he said: “Learn from me your rituals [of Hajj].” Narrated by Muslim (1297), from the hadith of Jabir.

Tawaf should encompass all of the Ka`bah.

If a person goes through the Hijr in order to make it shorter, this is not tawaf. Whoever does that, his tawaf is not valid. See the answer to question no. 46597 .

 He should perform tawaf on foot, if he is able to walk.

This is the view of the majority of scholars, apart from the Shafi`is.
Shaykh Ibn ‘Uthaymin (may Allah have mercy on him) said:
“What appears to me to be the case is that it is not permissible to ride whilst performing tawaf, whether on a camel or on people’s shoulders or in a wheelchair, unless there is a need for that. What constitutes need is matters such as sickness or old age, or if a person finds the crowding to be severe and he cannot stand it, because when it is crowded, some people can put up with it and some cannot. What matters is that if there is an excuse, there is nothing wrong with it, but if there is no excuse, then it is not permissible.” (Sharh Kitab al-Hajj min Sahih al-Bukhari (1/83)

The circuits must be done consecutively

This has been discussed in detail in the answer to question no. 219227 .

Tawaf must be done within the confines of al-Masjid al-Haram.

That is because what is required of the Muslim is to circumambulate the Ka`bah; if he does tawaf outside of the mosque, then he has circumambulated the mosque, not the Ka`bah.
Shaykh Ibn ‘Uthaymin (may Allah have mercy on him) said:
“The scholars said: In order for tawaf to be valid, it is stipulated that it should be within the confines of al-Masjid al-Haram; if someone does tawaf outside the mosque, then it is not valid. If someone wants to go around al-Masjid al-Haram from the outside, then it is not valid, because in that case he will have circumambulated the mosque, not the Ka`bah. As for those who do tawaf inside the mosque itself, whether on the upper or lower floors, their tawaf is valid. Based on that, one should avoid doing tawaf in the Mas‘a or on its roof, because the Mas‘a is not part of the mosque.” (Tafsir Surat al-Baqarah)

Tawaf should begin from the Black Stone.

If it begins from the door of the Ka`bah then the tawaf is deficient and is not valid.
Shaykh Ibn ‘Uthaymin said:
“Some people begin from the door of the Ka`bah and not from the Black Stone. The one who begins his tawaf from the door of the Ka`bah and completes it on that basis is not regarded as having completed tawaf, because Allah, may He be exalted, says (interpretation of the meaning): “Then let them … perform Tawaf around the ancient House” [al-Hajj 22:29]. The Prophet (blessings and peace of Allah be upon him) began from the Black Stone, and he said to the people: “Learn from me your rituals [of Hajj].” If a person begins from the door, or from a point that is not in line with the Black Stone, even by a short distance, then this first circuit that he begins in this manner will not count, because it is not complete, and he must do another circuit to make up for it, if he remembers shortly afterwards, otherwise he should repeat tawaf from the beginning.” (Majmu‘ al-Fatawa)
These are the conditions of tawaf, without which it is not valid.
With regard to the obligatory parts of tawaf, some scholars are of the view that it is obligatory to pray two rak‘ahs after completing tawaf, but the correct view is that this is Sunnah in the sense of being mustahabb (recommended). This is the view of ash-Shafi`i and Ahmad.
Shaykh Ibn Baz (may Allah have mercy on him) said concerning the two rak `ahs of tawaf: “It is not essential to do them behind the Maqam; rather the two rak‘ahs are valid in any place in the Haram, and if someone forgets them, it does not matter, because they are sunnah and are not obligatory.” (Majmu‘ Fatawa ash-Shaykh Ibn Baz (17/228)
Obligatory parts of tawaf
With regard to the other obligatory parts of tawaf mentioned by the scholars,  some of them are among the conditions mentioned above, but some of the scholars regarded them as obligatory parts of tawaf and not as essential prerequisites or conditions. (See a paper entitled Shurut at-Tawaf by Dr. ‘Abdullah az-Zahim, in Majallat al-Buhuth al-Islamiyyah, issue no. 53, and another paper of his (in issue no. 58) entitled Wajibat at-Tawaf)
And Allah knows best.