I downloaded iOS 14.4 but installation is giving error

Hi

Try these links - especially the second two.

Update your iPhone, iPad, or iPod touch

https://support.apple.com/HT204204

If your iPhone, iPad or iPod touch won’t update

https://support.apple.com/HT201435

If you see an error when you update or restore your iPhone, iPad, or iPod

https://support.apple.com/HT201210

What's the error message?

Restart it and try the update again.

The error message says “Unable to Install Update.

An error occurred installing (null)

Had done that several times... shut it down then tried installing the downloaded update