I want to upgrade my phone

Update your iPhone, iPad, or iPod touch

• If you have an iPhone 5S or 6/6plus, the highest you can update to is 12.5.6

• If you have an iPhone 6S through 7, you can update to 15.7

• If you have an iPhone 8 or higher, you can update to 16.0.2

Go to Settings > General > Software Update.

Update your iPhone, iPad, or iPod touch using WiFi -

Update your iPhone or iPad - Apple Support

Update using your computer -

Update iOS on iPhone - Apple Support

Your question is unclear. Do you want to upgrade your iPhone (for example, from a 13 to a 14) or update your device (such as iOS 15 to 16)?

If you want to buy a new phone, see here - iPhone - Buying iPhone - Apple

If you want to update your device, see here - Update your iPhone or iPad - Apple Support

Should you run in to any issues while doing either, please post back with relevant information - Writing an effective Apple Support Commun… - Apple Community

It looks like you are asking how to update the iOS on your iPhone. To do so, select Settings > General > Software Update. If your iPhone is eligible for an update, you will be prompted to do so. If not, your phone is already at the highest iOS.

Hello ~ You want to upgrade or update?

Update your iPhone or iPad - Apple Support

Apple Trade In - Apple

~Katana-San~