styles

editing the style instead of the text is the key idea: a style is the single shared formatting rule behind every paragraph tagged with it, so changing the rule once changes every paragraph at once, which is exactly what "automatically update all text" is testing for. If you formatted one heading by hand, you could right-click the style → Update HubHeading to Match Selection, which reads your hand-formatted example back into the shared rule and does the same job in reverse. Do not apply All Caps by typing in capitals, because that changes the text (the actual letters stored in the document) rather than the formatting — a search for the original mixed-case words would then fail, and the change wouldn't be undone by reverting the style.