This is just a place to get started. I'm not endorsing any of these, and am just making up a list to help with your search.
Some of these online Wicca courses are nothing more than a series of automatic emails that guide you through some topics, and some include scheduled chat sessions, assignments and message boards.
Some of these are individual witchcraft or Wicca courses, but some sites actually have several classes to choose from. You'll have to check them out to see what they all offer before signing up.
I figured I'd add a few more that aren't free, just in case you aren't worried about the cost. Just because they have a fee, doesn't necessarily make them better, but it's just another option to look into.
For these places that charge a fee, I cannot guarantee the quality of the courses or the service you are going to get for your money.
When you're first starting a study into Wicca or witchcraft, it can be very helpful to have a little guidance as you navigate the introductory basics.