How can I install iOS 12?

If you're trying to do it wirelessly, read this support guide:

Get help with over-the-air iOS updates - Apple Support

If you stll can't update, try and do it via ITunes (now 12.9.version) on a computer.

If you don't have a computer, borrow one from your friends, or contact your most convenient Apple Store and they will help you.

Regards

Giulio

I'm just a user like yourself, and you're not addressing Apple here.

I didn't intend to waste your precious time. Just tried to help you, and if I wasn't able to do it, I'm sorry about that.

If you want to inform Apple directly, please submit your comments here: Product Feedback - Apple

Regards

Giulio

there are several things you can try. 1. go to settings>general>reset>reset network settings. 2. Force restart the device by holding the side button and the home button down until you see the apple logo. 3. plug your phone into your iTunes computer using a USB and see if it will update then.

Why should i borrowe computer?

Immediately solve this problem . Apple company waste off my valuable time . This is company mistake .solve immediately. These are company values?

We are not Apple employees. We are volunteers. Please show some gratitude for the free help we are trying to give you.

I know sir . Send me Apple company custmor service mail I’d. Why should support for Apple. This is private company .

Call the number at the bottom of the screen.