Generally the male tree produces only male flowers which are hanging down from stalks. The flower look like long bell shape with filamentous anthers.
Female tree produces only female flower which are white or yellow in color with visible ovary at the base , stamens in the middle but without stigma. And need male tree for pollination.
The bisexual or hermaphroditic papaya tree produce flowers which contain both male and female organs. This flower usually emerge from bases of the leaves with ovary and stamens.
Some may produce individual male and female flowers in the same tree which don't require other tree for pollination.

You have to wait until it flower to determine the sex of the tree. If it turn out to be male tree, severe pruning can transform a male to a female plant. We have addressed this topic in detail earlier
https://www.plantvillage.org/en/quest...

For propagation and general care please check our papaya entry
https://www.plantvillage.org/en/topic...