I have white things that look like little strings on my orange tree as well as aphids, but I have no idea what they are.

These are green lacewing eggs. You will see their eggs at the end of long thread-like white stems.
Often these are laid on window panes or undersides of vegetable leaves.
The larvae are also called aphid lions, because they devour aphids.
Aphid Lions also like to eat red mites that attack citrus.
Green lace wings , Chrysoperia carnea, and their larvae are considered beneficial predators.

Lucky you.... those are good bugs!