Hadith #801 (Sahih Muslim)
Book: The Book of Prayers
Narrator(s): Mansur bin 'Abdur Rahman bin Talha منصور بن عبد الرحمن بن طلحة الحجبي
Grade: Sahih

” Then he may choose any supplication which pleases him or which he likes.”

Source: https://parallelquran.com/hadith/sahih-muslim-801/