How do I add SIRI to my iPhone 11 mini?

Siri is part of the operating system. It can't be removed from the phone.

Use Siri on all your Apple devices - Apple Support

Check Settings>Screen Time to make sure you don't have any restrictions enabled.

It is installed

Have a look in your settings to see if it is toggle on

Setting>Siri & Search>

It has everything to do with whether you even have an iPhone or some kind of cheap knockoff being sold by a con artist somewhere...

As already stated, Siri is baked into iOS. There is nothing to install...

Where, EXACTLY, did you get it and what are the model name and number in settings?

Captaincz wrote:

That's how Apple kept referring to it!

Um... no.

They would not call it an "iPhone 11 mini".

Check Settings>General>About.

What does it say in Model Name, and what does it say in Model Number?

Captaincz wrote:

How do I add SIRI to my iPhone 11 mini? And why would a phone come without SIRI installed?

Use Siri on all your Apple devices - Apple Support

And there is no iphone 11 mini by the way

Captaincz wrote:

That's how Apple kept referring to it!

Where is Apple calling it an "iPhone 11 Mini"?