Flow Byte

This plugin will let you add Google Ads conversion codes given by Google. 
This includes adding scripts in the head section of your website, to display them on specific pages, checkout or contact form (contact form 7)

Conversion Helper

This plugin will let you add Google Ads conversion codes given by Google.

Tobias Lindgren

The Freespee Call Tracking plugin dynamically displays a phone number on your WordPress site. Every phone call made by your visitors is turned into useful data. With the flip of a switch you deliver this phone call data to your Google Analytics account to see what keyword and Ad that drove the phone call.
Some of the features:
<ul>
<li>Link phone calls made by your online visitors to their source (Google SEM, Facebook, etc).</li>
<li>View the full online user journey including phone calls.</li>
<li>Feed call data into 3rd party platforms, like Google Analytics or Google AdWords. <a href="http://freespee.com/plugin-gallery" rel="nofollow ugc">Full list here!</a></li>
<li>For more information please visit <a href="http://freespee.com/" rel="nofollow ugc">Freespee.com</a>.</li>
</ul>
This plugin works in USA, Canada and Europe.
PS: You will need an <a href="http://freespee.com/sign-up/basic" rel="nofollow ugc">Freespee.com customer ID</a> to use this plugin. Sign up for free!

Freespee Call Tracking

See which visitors ended up calling you, no coding required. Automated delivery of phone call data to your Google Analytics account.

Conversion Helper vs Freespee Call Tracking