نَوَيْتُ صَوْمَ غَدٍ مِنْ شَهْرِ رَمَضَانَ، خَالِصًا لِلَّهِ تَعَالَى
Transliteration
Nawaytu sawma ghadin min shahri Ramadana, khalisan lillahi ta'ala
English meaning
I have intended to fast tomorrow from the month of Ramadan, purely for the sake of Allah Almighty.
When is it recited?
At suhoor before fajr.
Source
Hanafi jurisprudence