After completing your meal, you should recite this dua after eating:
اَلْحَمْدُ لِللّٰهِ الَّذِيْ أَطْعَمَنَا وَسَقَانَا وَجَعَلَنَا مُسْلِمِيْنَ
Alhamdu Lillāhilladhī At’amanā Wa Saqānā Wa Ja’alanā Muslimīn
Meaning: All praise is to Allah, Who gave us food and drink, and made us Muslims.
– Abu Daud, Hadith: 3850; Tirmidhi, Hadith: 3457