Apple Intelligence is not enabled on my iPhone 16 Pro Max

Here are Apple's published System Requirements for access to Apple Intelligence features. As you are in the UK - and not the US - pay particular attention to the two key settings required to enable the feature:

Settings > Apple Intelligence & Siri > [Siri Requests] Language - set to US English

Settings > General > Language & Region > [Preferred Languages] > Add Language - select US English

Apple Intelligence requirements for iPhone, iPad, and Mac

• iPhone 16, iPhone 16 Plus, iPhone 16 Pro, iPhone 16 Pro Max, iPhone 15 Pro, or iPhone 15 Pro Max; any iPad with A17 Pro or M1 and later; Mac with M1 or later
• iOS 18.1, iPadOS 18.1, or macOS Sequoia 15.1
• Device language and Siri language set to a supported language
• 4 GB of storage1

Learn how to free up storage on your iPhone, iPad, or Mac.

Supported languages: Apple Intelligence is available in English (US) in most regions around the world. In December, Apple Intelligence will add support for English (Australia), English (Canada), English (Ireland), English (New Zealand), English (South Africa), and English (UK). Over the course of the next year, Apple Intelligence will expand to more languages, like Chinese, English (India), English (Singapore), French, German, Italian, Japanese, Korean, Portuguese, Spanish, Vietnamese, and others.

After you have turned on Apple Intelligence, it will continue to work when you travel to other regions around the world.

For European Union residents: Apple Intelligence is available with macOS Sequoia 15.1 on supported Mac models. For iOS 18.1 and iPadOS 18.1, Apple Intelligence will not currently work if you are in the EU and if your Apple Account Country/Region is also in the EU. If traveling outside of the EU, Apple Intelligence will work on your iPhone or iPad if your language and Siri language are set to a supported language.

For China residents: Apple Intelligence will not currently work for supported devices purchased in China mainland. For supported devices purchased outside of China mainland, Apple Intelligence will not currently work if you are in China mainland and if your Apple Account Country/Region is also in China mainland.

When Apple Intelligence is available in the EU or China mainland, previously purchased devices that support Apple Intelligence will be able to activate and use it in that region.

The full System Requirements text can be accessed here:

How to get Apple Intelligence - Apple Support

A phone purchased directly from Apple in the UK shouldn't have an issue running Apple Intelligence. You should not have needed, nor would it help to change your address to a US address. You don't need to change your region at all. You DO need to make sure that your language and Siri language is set to US English.

I'd schedule an appointment at your Apple Store Genius Bar and let them help you in person.

Who did you purchase the iPhone from and what country were you in when you purchased the iPhone?

Do you live in the US? If no, where do you live?

Also, what is the model of your iPhone? Open Settings App > General > About > Model

If by chance it ends in CH/A, that would be an iPhone made for the China Market and no matter where you live, it can't have Apple Intelligence until it is approved for use in China.

Streanger wrote:

Far as I know the old mate in China

"Made in China" and "Made for Sale in China" are very different things. Most iPhones are made in China, though more and more are made in India. Phones made for sale in China have certain modifications required by the Chinese government. One of those modifications prevents the use of Apple Intelligence.

I'm guessing they told you that you need to set the language to English (U.S.)? And in what country did you buy the phone?

If nothing else helps, I'd take the refund and buy another one.