Hey, 

I am new here. If I want to share races that I have created on here, with my friends, do I need to share them with the entire community? What does Sharing your homebrew creations look like? Are there settings on who you can share your creations with, or is it basically the only way I can get my friends to see my creations, I have to share with everyone on the site? Just asking because a lot of the creations I have begun working on are from novels I am working on.

I think the answer to all of your questions is: You do not need to publish your homebrew in order to share it with players in your campaigns.

perfect. So, when I am running a campaign, I can throw my creations into it?

You don't need to be the DM, just be in a campaign. I'm not sure if content sharing needs to be enabled, but I don't think it does.

I can confirm that content sharing does not need to be enabled to share homebrew.  I checked on that a while back in one of my own campaigns.