The Prophet (ﷺ) used to say:
اَللَّهُمَّ إِنِّي أَسْأَلُكَ الْجَنَّةَ وَأَعُوْذُ بِكَ مِنَ النَّارِ
Pronunciation
Allaahumma 'innee 'as'alukal-jannata wa 'A'oodhu bika minan-naar
Meaning
O Allah, I ask You for Paradise and seek Your protection from the Fire.
Source: Sahih. Abu Dawud: 792
Read the hadith
حَدَّثَنَا عُثْمَانُ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا حُسَيْنُ بْنُ عَلِيٍّ، عَنْ زَائِدَةَ، عَنْ سُلَيْمَانَ، عَنْ أَبِي صَالِحٍ، عَنْ بَعْضِ، أَصْحَابِ النَّبِيِّ صلى الله عليه وسلم قَالَ قَالَ النَّبِيُّ صلى الله عليه وسلم لِرَجُلٍ " كَيْفَ تَقُولُ فِي الصَّلاَةِ " . قَالَ أَتَشَهَّدُ وَأَقُولُ اللَّهُمَّ إِنِّي أَسْأَلُكَ الْجَنَّةَ وَأَعُوذُ بِكَ مِنَ النَّارِ أَمَا إِنِّي لاَ أُحْسِنُ دَنْدَنَتَكَ وَلاَ دَنْدَنَةَ مُعَاذٍ . فَقَالَ النَّبِيُّ صلى الله عليه وسلم " حَوْلَهَا نُدَنْدِنُ " .
Narrated Some Companions of the Prophet: AbuSalih reported on the authority of some Companions of the Prophet (ﷺ): The Prophet (ﷺ) said to a person: what do you say in prayer? He replied: I first recite tashahhud (supplication recited in sitting position), and then I say: O Allah, I ask Thee for Paradise, and I seek refuge in Thee from Hell-Fire, but I do not understand your sound and the sound of Mu'adh (what you say or he says in prayer). The Prophet (ﷺ) said: We too go around it (paradise and Hell-fire). [Sahih (Albani). Abu Dawud: 792]
Duas from IslamicAPI's Masnun Dua dataset (based on the Quran, hadith, Hisnul Muslim and Rahe Belayat). See the dataset