Update my iPhone 6 iOS 12.1 to iOS 14.5

Hello,

Here are two different ways to ensure the highest iOS that your device will support is installed on your device.

For instructions about updating your iPhone, iPad, or iPod touch wirelessly, click here --> Update your iPhone or iPad - Apple Support

Here are instructions about how to update your iPhone, iPad, or iPod touch with the Finder on a Mac computer --> Update your iPhone, iPad, or iPod touch with the Finder - Apple Support

When updating, your device will update to the highest version currently available that it will support, or it will just say it is up to date and can't install a higher version. Only iOS 12.5.7 is currently available for an iPhone 6

You cannot update an iPhone 6 to iOS 14, as it only supports ios 12 due to hardware limitations, that iPhone is too old.

You can update from iOS 12 to iOS 12.5.7 tho, for the latest security fixes, but this will not let you be able to run newer apps that need iOS 14 or above.