How do I add Add Modifier to the UI In the online manual it shows a panel with a drop-down for selecting modifiers to add. I can't find that anywhere and no one seems to know anything about it? Is the manual wrong? Does that not exist? Is there a way to make Add Modifiers available via the UI?

https://www.blender.org/manual/modifiers/introduction.html#interface
In the properties panel you have the tab for the modifiers. If you click on add modifiers you can choose different modifiers