Can macOS display a key shortcut when the cursor hovers over a visible control? Is there a way to set the cursor so that when you hover over something it displays the keyboard shortcut like I can do on my pc? For example: if I hover over the Bold button in Pages it should show me the keyboard shortcut for that command.
There is nothing preventing the author of any specific app (Apple being the author of Pages in this case) from doing exactly what you ask for either by default or in a setting. 

Apple doesn’t have this as a standard affordable, so there’s no global switch you can run to have this enabled across multiple apps. The closest thing I can think of is the Cheat Sheet app which shows all active key shortcuts when you hold a key. It doesn’t select a button from the UI, though. 


Simplest way to capture &quot;keystroke representation&quot; to clipboard
Does OS X or Xcode have applications to manage cheat sheet/commands list?


The question covering Xcode also explains and demonstrates how to search for menu items by the help menu.