How to update iPhone 6s Plus?
Software update
[Re-Titled by Moderator]
Welcome, Psarivu, to Apple Support Communities!
We can see, from your screenshots, that you are trying to use a Hotspot, rather than a regular Wi-Fi.
You must use an actual Wi-Fi connection, in addition to having more than 50% battery charge, not on low power mode.
It would, also, be helpful to have your iPhone plugged in, to keep the Wi-Fi connection active if your iPhone goes to sleep.