أَسْتَغْفِرُ اللَّهَ، أَسْتَغْفِرُ اللَّهَ، أَسْتَغْفِرُ اللَّهَ. اللَّهُمَّ أَنْتَ السَّلَامُ وَمِنْكَ السَّلَامُ تَبَارَكْتَ يَا ذَا الْجَلَالِ وَالْإِكْرَامِ
Transliteration
Astaghfirullah, astaghfirullah, astaghfirullah. Allahumma antas-salamu wa minkas-salamu tabarakta ya dhal-jalali wal-ikram
English meaning
I ask Allah for forgiveness (3 times). O Allah, You are Peace and from You is peace. Blessed are You, O Possessor of majesty and honor.
When is it recited?
Recited immediately after giving salam.
Source
Muslim, Masajid 135, 591