There are many online resources available to help with career guidance. Try to avoid sites that may try to sell you something, get you to enroll in a for-profit program, or encourage you to sign up for a paid account.
In general, try to use websites ending in .gov, .edu, - and with a little more caution - .org. See below for some of the more reputable examples. And as always, go to the Career and Transfer Center or Ask a Librarian if you need more assistance.