How to Use Magic Keyboard to Shutdown iMac M1

On the keyboard that came with the computer, the top right button has a padlock emblem and is, I expect, therefore intended for locking and unlocking the screen. It functions as described: "Lock your iMac. Quickly press Touch ID or the Lock key … To unlock your iMac, lightly touch Touch ID, or press any key and type your password." (Magic Keyboard – Apple Support (AU))

The only Power Button—the one you press to start it up—is located at the back of the computer (lower left side, when facing the screen)

On my 24" M1 iMac, after pressing the Power Button – located at back of computer, the screen displays to fields in the middle: i) Username; ii) Password. At the bottom of screen are three 'buttons' labelled Shutdown, Restart & Sleep. As previously stated, I have not yet found a way to activate the buttons with the cursor, nor do I know of an keyboard actions that might cause them to function in the ways their names would suggest they should.

I agree that an orderly shutdown is preferable. That is why I am trying to find out if Apple has included a means of shutting down: i)using keyboard shortcuts – instead of clicking on the apple symbol, then selecting Shutdown from the dropdown menu; ii) after one has pressed the Power Button, but before logging in.

It seems to me bizarre, that one must log-in to be able to shut down!

Ok. To whoever may read this post:

i) If one wants to shut down an iMac such as I have, after starting-up but prior to logging in, press and hold the Power Button for at least 10 seconds – any less, and the computer will restart. This is an imprecise but effective procedure.

ii) Having logged in to the computer, it can be at any time be turned off by pressing on the 'control', 'option' and 'command' keys – with the right hand is easiest, and pressing the Power Button until the screen goes black – use the left hand.

Hi, hcsitas, sorry I misread my screen and didn't specifically reply to you. Firstly, I certainly can use my mouse/trackpad to click on the apple symbol etc., indeed I that is my usual way of ending a session. It's really a minor inconvenience to have to take my hand away from the keyboard, engage with the trackpad (in my case), and go through the procedure already described. However I can see the advantage that my Windows using friend claims is available to them: when in the middle of typing, one is called upon to quickly go elsewhere, to be able to shutdown with a couple of keystrokes.

Of more immediate use to me: to be able to use a few key strokes to shutdown the computer before I have logged in. To date, each time I have tried simply pressing and holding the Power Button, the screen – after briefly going black – restarts. What's the trick? Should I hold the Power Button for longer? If so, the possibility of shutting down with a few keystrokes, is quite appealing.