According to Islamic tradition, it is customary to raise a grave at least one hand above the ground level to signify that it is a grave, but not more than that. This practice is based on a narrative reported by Muslim and others from Harun that Thamamah ibn Shufayy recounted: “Once we were with Fadalah bin ‘Ubayd in the Roman land of Brudis. One of our companions died, and upon burying him, we were ordered by Fudalah ibn ‘Ubayd to level his grave. Then Fudalah said: ‘I heard Allah’s Messenger, peace be upon him, ordering people to level the graves of the deceased.'”

Some scholars act upon this opinion, disapproving of raising the grave more than necessary to indicate that it is a grave, so people will not step or sit on it. The Muslim authorities used to destroy cemetery structures not permitted by the law in accordance with the authentic sunnah. It is preferable not to erect a structure over a grave or to whitewash it, for it resembles decoration and vanity, which are inappropriate for the occasion of death.

It is allowed to place a mark, such as a stone or a piece of wood, on a grave to identify it. However, building mosques or placing lights on graves is not allowed, as there are many sound and clear hadiths that prohibit it. Similarly, slaughtering animals on graves is forbidden, as it was a practice of the Days of Ignorance and is not permissible in Islam.

It is not permissible to sit on, lean on, or walk over a grave. The Prophet, peace be upon him, prohibited whitewashing, writing on, or building on graves, and he cursed the women who visit graves and those who build mosques and place lights on them.

Placing Decorations on a Grave:
Decorating graves with flowers, candles, or other items is not allowed in Islam. This is because such decorations are considered a form of showing off, and death is a time for humility and submission to Allah. The Prophet Muhammad (peace be upon him) said: “Do not make my grave an idol to be worshipped” (Sahih Bukhari).

Prohibition of Cursing the Dead:
It is forbidden to curse the dead or wish them harm, even if they were disbelievers or enemies of Islam. The Prophet (peace be upon him) said: “Do not curse the dead, for they have already received their punishment” (Sahih Muslim).

Visiting Graves:
Visiting graves is recommended in Islam, as it reminds us of our mortality and the inevitability of death. However, there are certain guidelines that should be followed when visiting graves. For example, one should seek permission before entering the cemetery, greet the deceased with the Islamic greeting of “peace be upon you,” and make dua (supplication) for the deceased. It is also recommended to recite Surah al-Fatiha and Surah al-Ikhlas while visiting graves.

Conclusion:
In summary, there are certain etiquette and guidelines that Muslims should follow regarding graves and cemeteries. It is important to respect the dead and their resting places, and avoid any actions that may be disrespectful or showy. Visiting graves is encouraged in Islam, but it should be done with humility and respect, and in accordance with the guidelines set by the Prophet Muhammad (peace be upon him).