Put a file in the root of your website folder.
Put this in the file if you dont want your site indexed.
User-agent: * Disallow: /
For more info about robots:
http://www.robotstxt.org/wc/robots.html [3]
And for syntax:
http://www.sxw.org.uk/computing/robots/check.html [4]
Links
[1] https://dominiquedecooman.com/blog-topics/seo
[2] https://dominiquedecooman.com/blog-topics/standards
[3] http://www.robotstxt.org/wc/robots.html
[4] http://www.sxw.org.uk/computing/robots/check.html