I have downloaded iOS 15.8.2 on my iPhone 6s but not yet installed what can I do?

abdulhammed272 wrote:

I want to update my iOS 13.5 to iOS 15,8.2 on my iPhone 6s and it has been downloaded but not yet installed

You’ll need sufficient free space to install, a Wi-Fi connection, and no add-on VPN client apps installed.

The Settings > Software Update page usually lists any issues or limits encountered by the install.

Circled in blue is an example of an installation error:

Here is what to do: If your iPhone or iPad won't update - Apple Support

15.8.2 is indeed the “current” iOS for a 6s.

Your question is not clear.