Heard the last atayya on a salaat has addiditon du'ah after its recitation. Is that true and what's the du'ah.
Bismillah. Alhamdulillahi rabbil-'alamin was-Salatu was-Salam 'ala Sayyidil-Mursalin wa 'ala 'Alihi wa Sahbihi Ajma'in.
After Attahiyat, aka Tashahhud, in the last rakaat of Salah the worshiper recites Salawaat, then makes duas, then performs Taslim saying Salaam to his right and left with which Salah ends. This is the only diffirence between the previous rakaats and the last rakaat in Salah consisting more than two rakaats. Tashahhud, or Attahiyat, itself is always the same.
Indeed, there are various versions of Tashhahud which are related in the Sunnah of the Prophet (sallahu alayhi wa sallam).
For instance, there is this hadith in al-Muwatta of Imam Malik (rahimullah) https://sunnah.com/malik/3/57 that the Sahabi Ibn Umar (radi Allah anhu) did this version of the Tashhahud in the first sitting differently, than in the last one. And that he also made Du'a in the first sitting, which is also indicated in ahadith like in Sunan an-Nasa'i, but also in the book "Collection of Authentic Invocations" by Sheikh Albani that it is mustahhab to do that.
The Tasmiyah, which is the "Bismillah" that is mentioned in the beginning, and also related in Al-Bayhaqi, should not be recited as Al-Bukhari, An-Nasai, and others state (Al-Kubra 2/202-205, Al-Awsat 3/211, and others) because that has no basis in the Sunnah.