Hi there, I recommend you search for robots.txt and disallow search engine crawling or similar in your favourite search engine. If you are using a somewhat recent version of Matomo, we also disallow Matomo being indexes through Meta tags

Yes I know that but how should this file looks like?
Matomo domain is subdomain.example.com
So in robot txt I should att this?:

User-agent: *
Disallow: subdomain.example.com

And where this file should be placed? In main domain or matomo subdomain?

@MESWEB I'd recommend you to make sure you are using the latest Matomo version as it contains a line like this

<meta name="robots" content="noindex,nofollow">

that tells search engines to not index this page.

@Findus23 Yes I do. I have Matomo 3.13.0

This line is visible on login page but google all the time index this subdomain.
I was reading somewhere about google indexing and someone says:
Google is indexing even if content nofollow and noindex is added to html code because some website can link to this url. So he's recommend using robot.txt file.
https://support.google.com/webmasters/thread/12775313?hl=en