Your Mighty Network has 4 main privacy options: public, private, secret and plan access.
Check out the details for your privacy options in the article, What are the Privacy Options I Have When I Set Up My Mighty Network?
To change your privacy level, click on your profile picture in the top right corner > Admin > Setup > Privacy & Access.
If you are looking to change your privacy setting from plan access to public, private, or secret, check out this article.