the Bible, the chief official of Babylon changed the names of Daniel and his three friends to erase their Hebrew identities and assimilate them into Babylonian culture. [1, 2, 3]

The original Hebrew names—which honored the God of Israel—were replaced with new names dedicated to Babylonian pagan gods. [1, 2]

• Daniel (meaning “God is my judge”) became Belteshazzar (meaning “Bel protect his life”).
• Hananiah (meaning “Yahweh has been gracious”) became Shadrach.
• Mishael (meaning “Who is like God?”) became Meshach.
• Azariah (meaning “Yahweh has helped”) became Abednego (meaning “Servant of Nabu”). [1, 2]

You can read more about their time in exile and why their names were altered in the Bible Study Tools Daniel 1:7 Commentary or this GotQuestions Study on Daniel and Belteshazzar.