Recite this dua to express gratitude and appreciation towards someone who has done a favor, shown kindness, or helped in any way. It's a way of acknowledging and thanking the person while also supplicating Allah to reward them for their benevolence. Therefore, it's recited to show gratitude and to invoke blessings upon the person who has done a good deed.
جَزاكَ اللهُ خَـيْراً
(Jazaakallaahu khayran)
May Allah reward you with good.
خدا آپ کو جزائے خیر دے۔
ঈশ্বর আপনাকে পুরস্কৃত করুন
भगवान तुम्हें पुरस्कृत करें