How do I uninstall the latest iOS update on my iPhone?

That is not possible.

If you tell us specific things you cannot do or don’t care for, perhaps we can assist further. Tell us what you’re trying to accomplish, not how you’re trying to do it.

how to fix my email where it’s not divided up into sections please

Open Mail

Tap on the 3 dots in the upper right corner of the window

Select List View

If you want the icons that are next to each email to go away.......

Tap Settings

Scroll down and tap Apps

Tap Mail

Turn Off Show Contact Photos

More information is here if you have an. iPhone 16 model or iPhone 15 Pro or iPhone 15 Pro Max.

Use Apple Intelligence in Mail on iPhone - Apple Support

Unfortunately, your question assumes that things can be undone, when they can't.

Maybe we can help if you can provide some details on what you are having difficulty with.