Hi, i have iphone 6s,how to update os 14,

Your profile tells us you have an iPhone 6, not an iPhone 6S.

The iPhone 6 can update as far as iOS 12.5.5. If that is what is installed on your phone, there are no more updates available for your phone.

So the question would be......what iOS version is currently installed on your phone?

If you do not know, tap Settings, then tap General, then tap About.

Look for Software Version

Hi there! You can update your IOS by following the article below

Update iOS on iPhone - Apple Support

Don't forget to back up your iPhone before updating!

How to back up your iPhone, iPad, and iPod touch - Apple Support

shahidss01 Said:

"Hi, i have iphone 6s,how to update os 14"

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Updating, the latest iOS version will be installed.

For reference...

Updating an iPhone:

How to do so...

Determine if an Update will Install:

A. Verify Compatibility:

Identify your iPhone model. The first thing that comes to mind in incompatibility being the culprit. So, confirm the model of your iPhone. If iPhone model is incompatible with iOS15 then it is because you iPhone does not meet the hardware requirements for this iOS version(s).

B. If Compatible...

1. Back Up First:

IMPORTANT: If you have an option to update, however, then be certain you backup your iPhone first. That way, you will have something to restore your iPhone from should anything go wrong with the update

then...

2. Proceed with the Update:

Use my User Tip:  Update your iPhone Using a Computer - User Tip

Are you sure you have a 6S and not a 6? Go to Settings>General>About>Model Number. What does it say?

Even if you have a 6S, you can't update it to iOS 14. You can only update to iOS 15.6.