On even older iPhones the button you need to press and hold is on the top of the phone.Then restart by pressing the Side button. If your iPhone has a Home button you can shut it down by pressing the Side button until the power off slider appears.To turn it back on press the side button again. Just drag that from left to right and wait for your iPhone to shut down. Eventually the power-off slider will appear. In that case you need to press and hold one of the volume buttons at the same time as the Side button.
How you turn off (or restart) your iPhone (or iPad) will depend on which model you own. It is often the fix all solution so it’s the best place to start. No tutorial would be complete without the stalwart advice “turn it off and on again”.
