Assalaamu alaykum wa rahmatullaahi wa barakaatuhu, Shaykhs. If I miss one or a few Takbeers (saying: Allahu Akbar) at the beginning of the Eid prayer, am I required to do something? May Allah reward you.

All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ‘alayhi wa sallam, is His slave and Messenger.

If someone missed the additional Takbeers (other than the opening takbeer [takbeerat al-ihraam]) in the 'Eed prayers with the imaam, the most likely correct view is that it is recommended for him to make up for them by saying them. He is not required to do anything if he missed them because reciting them is an act of Sunnah and their due time has passed.

Ibn Qudaamah wrote, “The Takbeers and Thikr (expressions of remembrance of Allah) between them (in the 'Eed prayer) are among the acts of the Sunnah, and reciting them is not obligatory; the prayer is not invalidated by missing them deliberately or forgetfully.” [Al-Mughni]

Allah knows best.