Some translations set poetry farther to the right than the rest of the text to show that it is poetry. The ULB does this with the poetry in 21:5,16 and 42, which is from the Old Testament.
Jesus rode into Jerusalem on an animal. In this way he was like a king who came into a city after he had won an important battle. Also, the kings of Israel in the Old Testament rode on donkeys. Other kings rode on horses. So Jesus was showing that he was the king of Israel and that he was not like other kings.
Matthew, Mark, Luke, and John all wrote about this event. Matthew and Mark wrote that the disciples brought Jesus a donkey. John wrote that Jesus found a donkey. Luke wrote that they brought him a colt. Only Matthew wrote that there were both a donkey had a colt. No one knows for sure whether Jesus rode the donkey or the colt. It is best to translate each of these accounts as it appears in the ULB without trying to make them all say exactly the same thing. (See: [Matthew 21:1-7](../../mat/21/01.md) and [Mark 11:1-7](../../mrk/11/01.md) and [Luke 19:29-36](../../luk/19/29.md) and [John 12:14-15](../../jhn/12/14.md))