I need to upgrade my iPhone

If you mean you want to buy a new one

https://apple.com

If you mean update the software,

Check

• you are on a good Wi-Fi,

• Plenty of spare storage – 6GB at least.

• on charge with more than 50% charged,

• low power mode turned off.

• Fully working cellular network connection via your SIM.

• Check Settings, General to make sure you have no Beta profile installed.

• no VPN installed (Check Settings, General, VPN & Device Management)

Resources:-

Update iphone

Update your iPhone, iPad, or iPod touch - Apple Support

Learn how to update your iPhone via recent Macs here:-->

Update your iPhone, iPad or iPod touch with the Finder – Apple Support (UK)

or older Macs and PC here:-->

Update your iPhone, iPad or iPod touch with iTunes – Apple Support (UK)

I want to upgade my iphone

If you mean you want to buy a new one go to

https://apple.com