How can I install my iOS update

how?

You donload it and doesnt install ?

or it cannot download anymore?

To see which model iPhone you have, select Settings > General > About. That screen will display the

• iOS version,
• model name and
• model version.

Please let us know what that says on your iPhone.

Please provide more information. Which iPhone do you have? What is its current iOS? What happens if you tap Install?