I want to upgrade my phone

If you want to upgrade the phone, buy a newer model phone.

If you want to upgrade the IOS, an iPhone 6 can't be upgraded past IOOS 12.5.6.

See the article(s) below. 

iOS 16 compatible devices

IOS 15 and iPadOS 15 Compatible Devices.  *

iOS 14 and iPadOS 14 Compatible Devices.  *

iOS 13 and iPadOS are compatible with these devices - Apple Support.  *

Shop one-on-one with a Specialist at an Apple Store.

Click ▶︎ Reserve a Shopping Session. 🛒