It wasnarrated from 'Abdullah bin Mas'ud that for the two Rak'ahafter Maghrib, the Prophet (ﷺ) used to recite:
"Say: O youdisbelievers!" [Al-Kafirun (109)] and "Say: He is Allah the One."[Al-Ikhlas (112)] (TR)
English reference (TR): Vol. 1, Book 5, Hadith 1166 (TR)
Arabic reference (TR): Book 5, Hadith 1221 (TR)