My iPhone 18 Pro Max with iOS 27 don't have Apple Intelligence in setting

Your iPhone 18 Pro Max supports Apple Intelligence, so the model itself isn’t the problem.

I’d check the language settings first. Go to Settings > General > Language & Region, and also check Settings > Siri > Language. Apple Intelligence requires both the device and Siri to use a supported language.

After changing either one, restart the iPhone and check Settings again. Also, if you’re specifically looking for Siri AI (Beta) rather than Apple Intelligence in general, its availability is more limited by language and region.

What language and region are currently set on the iPhone?

Sorry to say: I found this in Apple's Newsroom:

Siri AI, a profoundly more capable and personal assistant, is here - Apple

Eg: says:

"Siri AI will not be available initially in the EU on iOS, iPadOS, and watchOS. Features that rely on Siri AI will also not be available in the EU on iOS, iPadOS, and watchOS. Apple is working hard to find a path forward that preserves its users’ privacy and security."

and

"Apple Intelligence is available with Siri settings and device language set to Chinese (simplified), Chinese (traditional), Danish, Dutch, English, French, German, Italian, Japanese, Korean, Norwegian, Portuguese, Spanish, Swedish, Turkish, or Vietnamese.

Some features may not be available in all regions or languages."

Re: My iPhone 18 Pro Max with iOS 27 don't have Apple Intelligence in setting

If the iOS27 upgrade has fully completed downloading:

Wondering whether Apple Support's online articles can help:

How to: Get started with Siri AI on iPhone - Apple Support

Eg: says:

Turn on Siri AI

1. Go to the Settings app on a supported iPhone. 
2. Tap Siri, then do one of the following: 

• • If Siri is off: Tap “Turn on Siri,” then tap “Try Siri AI (Beta).”
  • If Siri is on: Tap “Try Siri AI (Beta).”

3.Follow the onscreen instructions.

and

How to: Get started with Apple Intelligence

Eg:says: "With iOS 27, Apple Intelligence is integrated across your apps"