What does Odysseus have to achieve during his voyage?
The main goal for Odysseus is to return home to Penelope and resume a peaceful life and rest from all his travails. He is sidetracked by all kinds of obstacles and so he ends up having new goals along the way but it is the overarching goal for his voyage.
Of course in another perhaps literary or heroic sense he also has to demonstrate his heroic abilities and his ability to defeat all foes placed before him in order to gain status as a true hero. He has to resist the temptations of Circes, he has to find a way out of the Cyclops' cave, he has to figure out a way past the Sirens, he has to also figure out a good way to destroy all the suitors and reclaim his home in heroic fashion.