Is showing gratitude to Allah done by verbally saying "Alhamdulillah" or by saying "Shukrullah"?

"Al-hamd" (praise) is more general than "al-shukr" (gratitude). "Al-shukr" is only in response to a blessing or benevolence, whereas "al-hamd" is for blessings and other things, such as praising good character. Some scholars have held that the two terms are synonymous. Ibn Manzur said, "Praise is the head of gratitude; no servant has thanked Allah who does not praise Him." Gratitude is not limited to the tongue; rather, it is with the heart through submission, with the tongue through praise, and with the limbs through obedience.