Google AdSense in my blog… how insert the code ?

Place your google adsense code into the sidebar.php (sidebar template) file for your current theme.

Or index.php, if it doesn’t have a sidebar.php.

There’s also a plugin available to let you add the code to posts.
https://philhord.com/wp-hacks/adsense

and AdRotator https://blog.taragana.com/index.php/archive/wordpress-plugin-adrotator-rotate-your-ads-including-adsense-dynamically/