what is the requirements to run MAC OS Monterey

See here: link-> How to upgrade to macOS Monterey - Apple Support

MacBook Pro introduced in 2015 or later

MacBook Air introduced in 2015 or later

MacBook introduced in 2016 or later

Mac mini introduced in 2014 or later

iMac introduced in late 2015 or later

iMac Pro

Mac Studio

Mac Pro introduced in 2013 or later

If upgrading from macOS Sierra or later, your Mac needs 26GB of available storage to upgrade. If upgrading from an earlier release, your Mac needs up to 44GB of available storage.

lazar89 wrote:

I have MacBook retina 12" early 2015, Os is BIG SUR 11.6.6

Why I don't have update to OS Monterey? It's just say that my OS is up to date.

A 2015 12" MacBook (not Air or Pro) is not compatible with Monterey as shown in previous posts.

MacBook Pro introduced in 2015 or later

MacBook Air introduced in 2015 or later

MacBook introduced in 2016 or later

Mac mini introduced in 2014 or later

iMac introduced in late 2015 or later

iMac Pro

Mac Studio

Mac Pro introduced in 2013 or later

MSGDD wrote:

what is the requirements to run MAC OS Monterey

macOS Monterey hardware requirements—

macOS Monterey - Apple

As multiple links and posts on this page indicate, you need a 2016 or later MacBook to run Monterey.

macOS Monterey is compatible with these computers

Is this computer listed as Compatible ?

The fist requirement is you own a Mac. Years ago, a "hacked" version was marketed that was not Apple branded, It was known as a "Hackintosh". A court case in Apple's favor effectively ended that practice in large part. It still can be done on a user basis, but the pieces and parts are very specific and it's very involved to get it going. There is obviously NO support for sure a machine.

Moral of the story: buy a Mac to run macOS.

Tips Monterey Upgrade 

I have MacBook retina 12" early 2015, Os is BIG SUR 11.6.6

Why I don't have update to OS Monterey? It's just say that my OS is up to date.