How do I update my iPhone 6plus

Hi Serratango

Update iPhone manually

At any time, you can check for and install software updates.

Go to Settings  > General > Software Update.

The screen shows the currently installed version of iOS and whether an update is available.

To turn off automatic updates, go to Settings > General > Software Update > Automatic Updates.

The latest IOS 15 is compatible with the iphone 6s Plus however the update roll outs will be staggered,

they will also be region and network dependant. Please be patient and check regularly.