It depends on where you want to put your ads. Here are some options:
- You can add adsense code to a text widget.
- You can add adsense code to the header widget and use css to put it anywhere.
- You can use a child theme’s functions.php file to create your own shortcode, which you could then use to put an ad anywhere in any post or page.
- You could use action hooks to put adsense code just about anywhere.
If you are looking for a plugin to handle your adsense code, think about where you want your ads placed (and how you want to place them — automatically or via a shortcode) and look for a plugin that handles it the way you want.
The good news is that there are lots of adsense plugins out there. The bad news is that not all of them will do what you want.
Good luck!
Ken