In this Dua, Prophet Yousuf (AS) thanks Allah because He has given him everything. He taught him to interpret dreams. He is the Lord of heavens and earth and protector in this world and in the Hereafter. He also asked Allah to make him among the righteous in the Day of Judgement.
“My Lord, You have given me [something] of sovereignty and taught me of the interpretation of dreams. Creator of the heavens and earth, You are my protector in this world and in the Hereafter. Cause me to die a Muslim and join me with the righteous.” Quran (Surah Yousuf 101)