Updated February 26th, 2020.
Those little items in the menubar– the clock, Spotlight, the battery level (on a laptop), WiFi signal, maybe one for Siri, maybe one for Time Machine– are really handy. They’re even handier when you can rearrange their order so the ones you want are where you want them. The secret to rearranging menubar icons: use the Command key as you drag them to position.
With the Command key held down you can drag any menubar icon to any position, allowing you to rearrange all you want. Here’s an example of before-and-after.
If you change your mind you can always put things back the way they were. There’s no “Undo” but you can hold the Command key down and drag menubar icons to any location in the bar that you’d like.
BONUS: if you want to remove a menubar icon just drag it off the menubar… while holding the Command key. This doesn’t always work but most of the time it does. (Of course you can always click on a menubar icon’ and see if there are preferences in its menu that allow you to hide the icon. That’s a good option too.)