100 times
((أَسْتَغْفِرُ اللَّهَ وَأَتُوبُ إِلَيْهِ)) (مِائَةَ مَرَّةٍ فِي الْيَوْمِ).
Edition transliteration
Astaghfirullaaha wa 'atoobu 'ilayhi[one hundred times a day]
Meaning
I seek Allaah’s forgiveness and I turn to Him in repentance.’ [one hundred times a day]
Source and references
Hisn al-Muslim, entry 96.The reference is copied from the edition; separate editorial verification is not complete yet.
Source edition: Fortress of the Muslim. Open source ↗