Why install now keeps buffering and can't click install now

Hello hikam176,

Thanks for posting in the Apple Support Communities. We're happy to look into this with you. In most cases correcting issues with updates for iOS is pretty straight forward. Have you had an opportunity to review article, If your iPhone or iPad won't update - Apple Support and try the recommended actions? If not, you might find the details here helpful, especially those outlined in section we've provided below:

If the download takes a long time

You need an internet connection to update your device. The time it takes to download the update varies according to the size of the update and your internet speed. You can use your device normally while downloading the update, and your device will notify you when you can install it. To improve the speed of the download, avoid downloading other content and use a Wi-Fi network.

Please let us know if this helps and if not, what the results for each troubleshooting suggestion was. This will help us narrow down possible troubleshooting options to recommend.

Best regards.