Go to Items.
Press the edit icon to the right of the product you want to add/update the visibility of.
Under WEB STATUS (or the name you gave web status attribute), select ACTIVE or VISIBLE.
Scroll down and press Save.
Make Product Visible Online
If you want to make a product visible on your online store, the first thing you need to do is create the web status attribute. Once you completed this step, you'll be able to make a product Visible, Not Visible, or Visible but Not Salable.