A public recipe will be listed when users searches for a recipe with queries that matches your recipe. A private recipe on the other hand, will have a sharing token at the end of the URL, in the format ?st=xxxxxx. This sharing token must be provided in the URL if someone else were to be able to access your recipe.
To toggle a recipe between Public and Private, go to the settings tab in your recipe, and toggle the switch to either on or off, depending on whether you want it to be public or not respectively. Do note that you have to stop the recipe first if it is already running. However, you will only be able to toggle to private recipes on one of our Paid Subscriptions. Find out more here.