At slaughter time, the Prophet (ﷺ) would say this dua -
بِسْمِ اللَّهِ اَللَّهُمَّ تَقَبَّلْ مِنْ مُحَمَّدٍ وَآلِ مُحَمَّدٍ وَمِنْ أُمَّةِ مُحَمَّدٍ
Transliteration
Bismillaahi, Allah-humma Taqabbal min Muhammadin wa Al-i-Muhammadin, wa min Ummati Muhammadin
Translation
In the name of Allah, O Allah, accept it from Muhammad, Muhammad's family and from Muhammad's Ummah (followers)
حَدَّثَنَا هَارُونُ بْنُ مَعْرُوفٍ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ وَهْبٍ، قَالَ قَالَ حَيْوَةُ أَخْبَرَنِي أَبُو صَخْرٍ، عَنْ يَزِيدَ بْنِ قُسَيْطٍ، عَنْ عُرْوَةَ بْنِ الزُّبَيْرِ، عَنْ عَائِشَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم أَمَرَ بِكَبْشٍ أَقْرَنَ يَطَأُ فِي سَوَادٍ وَيَبْرُكُ فِي سَوَادٍ وَيَنْظُرُ فِي سَوَادٍ فَأُتِيَ بِهِ لِيُضَحِّيَ بِهِ فَقَالَ لَهَا " يَا عَائِشَةُ هَلُمِّي الْمُدْيَةَ " . ثُمَّ قَالَ " اشْحَذِيهَا بِحَجَرٍ " . فَفَعَلَتْ ثُمَّ أَخَذَهَا وَأَخَذَ الْكَبْشَ فَأَضْجَعَهُ ثُمَّ ذَبَحَهُ ثُمَّ قَالَ " بِاسْمِ اللَّهِ اللَّهُمَّ تَقَبَّلْ مِنْ مُحَمَّدٍ وَآلِ مُحَمَّدٍ وَمِنْ أُمَّةِ مُحَمَّدٍ " . ثُمَّ ضَحَّى بِهِ . '
Translation
A'isha reported that Allah's Messenger (ﷺ) commanded that a ram with black legs, black belly and black (circles) round the eyes should be brought to him, so that he should sacrifice it. He said to 'A'isha: Give me the large knife, and then said: Sharpen it on a stone. She did that. He then took it (the knife) and then the ram; he placed it on the ground and then sacrificed it, saying: Bismillah, Allah-humma Taqabbal min Muhammadin wa Al-i-Muhammadin, wa min Ummati Muhammadin (In the name of Allah," O Allah, accept [this sacrifice] on behalf of Muhammad and the family of Muhammad and the Umma of Muhammad" ). [Muslim: 1967]
This dua asks Allah to accept sacrifice for Prophet Muhammad, his family, and all Muslims. Blessings and unity fill the act for the whole ummah.
Yes. Bismillah allahuakbar is required for halal sacrifice. Without these words, the meat is not halal even if a Muslim does the slaughter. Always say them first.
After you finish, say O Allah, accept from me this sacrifice like You accepted from Ibrahim and Muhammad. This prayer asks for acceptance.
The dua is Allahumma taqabbal minni kama taqabbalta min Khalilika Ibrahim wa Habibika Muhammad. Say this while you sacrifice during Eid al Adha.
During sacrifice, say Bismillah Allahu Akbar. This follows the Sunnah of Prophet Ibrahim. It is the right way for muslim prayer and qurbani during Eid ul Adha.
Say Bismillah, Allahu Akbar then Allahumma hadha minka wa laka hadha anni. Ask Allah to accept your qurbani. Remember to say the prayer for acceptance.