جَلَّاهَا

جَلَّاهَا is a verbal sentence  (الجُمْلَةُ الفِعْلِيَّةُ) consisting of a verb and an object in the form of a third-person, feminine, singular attached pronoun

فِعْلٌ وَمَفْعُوْلٌ بِهِمَفْعُوْلٌ بِهِ فَاعِلٌ فِعْلٌ
Verbal sentenceObject SubjectVerb
الجُمْلَةُ الفِعْلِيَّةُAttached pronounDetached pronoun
AccusativeNominative
Reveals itجَلَّاهَا=هَا+مُسْتَتِرٌ تَقْدِيْرُهُ هُوَ+جَلَّا
It reveals itit(it)reveals
Surah/Below is the only verse in the holy Quran containing the verb and third person, feminine, singular objectجَلَّاهَا
Verse
91-3and the day when it reveals it (the sun)وَالنَّهَارِ إِذَا جَلَّاهَا