After a deep tour of the books of fiqh, I present to you some information about the Day of Arafa:

First: What is it?
It is the ninth day of the month of Dhul-Hijjah.

Second: Arafa or Arafat?
There are many sayings about this:
The first: the meaning is one, and it is the place where the pilgrims stand on the day of Arafat, approximately 23 kilometers east of Mecca.
The second: Arafa is the name of the day and Arafat is the name of the place.
The third: Arafat is the plural of Arafa, and it is the spot on which one pilgrim stands.

Ruling on standing on Arafat:
The scholars are unanimously agreed that standing at Arafat is the greatest pillar of Hajj, when it was reported that the Messenger of Allah, may Allah bless him and grant him peace, said:
“الحج عرفة، من جاء ليلة جَمْعٍ قبل طلوع الفجر فقد أدرَكَ”
“Hajj is Arafat. Whoever catches up with the night of Arafat before dawn comes on the night of Jam (Al-Muzdalifah), his Hajj is complete.”

Etiquette of supplication on the Day of Arafah:
1- Complete purification (tahara) for one who is able (meaning with the exception of the menstruating woman and the postpartum woman).
2- Facing the Qiblah.
3- A lot of supplication (Duaa) for you and others and asking forgiveness from Allah.
4- Your heart’s feelings should be present.
Raising the hands when supplicating.
The most frequent supplication of the Prophet may Allah bless him and grant him peace, on the Day of Arafat was: “لا إله إلا الله وحده لا شريك له، ، بيده الخير وهو على كل شيء قدير”
“There is no God but Allah, He is One without any partner. All good is in his hands and He has power over all things.”
And also said
“أفضل الدعاء دعاء يوم عرفة، وأفضل ما قلت أنا والنبيون من قبلي لا إله إلا الله وحده لا شريك له”
“The most excellent dua is the dua on the Day of Arafa, and the best of what I and the prophets before me have said, is ‘There is no god but Allah, alone, without partner.”

May Allah accept from us and you all the good deeds