Some translations set each line of poetry farther to the right than the rest of the text to make it easier to read. The ULB does this with the poetry in 1:5, 7-13, which are words from the Old Testament.
The author uses rhetorical questions as a way of proving Jesus is better than the angels. Both he and the readers know the answers to the questions, and the writer knows that as the readers think about the answers to the questions, they will realize that God's Son is more important than any of the angels.
Jewish teachers, like the Old Testament prophets, would put their most important teachings in the form of poetry so that the hearers would be able to learn and remember them.