My phone is alwaus showing " update request" and just loading ... but it didnt update or even start updating ... so what shall i do to update the system??

Turn off Low Power Mode; charge the battery to 50% or higher and try again.

To update your phone go to Settings/General/Software Update and follow the instructions.

There are several ways to download photos, all explained here→Copying personal photos and videos from iPhone, iPad, or iPod touch to your computer.

Apps are never stored in iCloud.

How to update my iPhone.

And how to download photos and app on iCloud