Is the Ta'awwudh (seeking refuge with Allah) obligatory in every rak'ah, or is it sufficient in the first rak'ah?

Allah has commanded seeking refuge from the accursed Shaytan when reciting the Qur’an. The majority of scholars consider it to be mustahabb (recommended), while others view it as wajib (obligatory).

Among its forms are: "A‘udhu billahi minash-shaytanir-rajim" (I seek refuge with Allah from the accursed Shaytan), or "A‘udhu billahis-sami‘il-‘alim minash-shaytanir-rajim" (I seek refuge with Allah, the All-Hearing, the All-Knowing, from the accursed Shaytan).

Seeking refuge (isti‘adha) occurs both inside and outside of prayer. It suffices to recite it once at the beginning of the first rak‘ah, and it is preferable for it to be recited before the recitation (of the Qur’an), not after it.