Changing the order of the Mail opions in the upper list
I wish to change the order of the top option in Mail - Filter View options New message etc
iMac 24″, macOS 15.5
Seems you wish to customize the toolbar at the top of Mail app.
(My current MacOS is an earlier version, so hope this will work for you on your iMac.)
Right click a blank space (or one of the icons) on the toolbar.
A small menu should open, giving you the option "Customize Toolbar"
Clicking that option opens a window where you can add to, or change the order of, the icons.
(The icons already at the top can now be dragged to where you want them)
Click "Done" when happy with the customized toolbar to save the changes.