If you want to make an attribute (product characteristic) visible on the product page, follow these steps:
1. Click on 'Stores' and then click on 'Products' (which is found under the 'Attributes' section).
2. Select or search for the desired attirbute and then click on it.
Once the attribute opens, you can see all the 'Attribute Information' tabs.
3. Click on 'Storefront Properties' tab (the 3rd tab) and then change the 'Visible on Catalog Pages on Storefront' field to Yes.
Note: To make sure your changes are saved, remember click on the 'Save Attribute' button.