How does Wheatley's use of imagery contribute to her purpose in the poem? (To His Excellency, General Washington)

Wheatley personifies America through the use of the character Columbia who is very much a goddess. ... Through the allegorical figure of Columbia, the poem uses a glamorous image to personify the states and the fight for independence. The figure of Columbia serves (or functions as) a guide for General Washington. Very sorry if I get this wrong. I'm in 5th grade. ♥