jonashellmann

This plugin lets you integrate your existing Matomo On-Premise into WordPress. If you don’t already have a working Matomo (either <a href='https://matomo.org/matomo-on-premise/' rel="nofollow ugc">On-Premise</a> or <a href='https://matomo.org/hosting/' rel="nofollow ugc">Matomo Cloud</a>), use the <a href='https://wordpress.org/plugins/matomo/' rel="ugc">Matomo Analytics</a> plugin instead.
Matomo, formerly called Piwik, is an self-hosted open-source tool to analyze your pages. It needs a tracking code to be included in the pages that should be monitored. Also campaigns can be created by using specific parameters in the URL.
Therefore in this plugin, you can configure the URL where Matomo is hosted and the site ID for tracking your WordPress page. You can find it in the tracking code. You only need to fill in these both information. The rest of the tracking code is standartized and automatically inserted in the page. Also, you can set a campaign name (pk_campaign) and source (pk_source) which will be adds to the links in your RSS feed. This helps you to analyze how many users enter your pages by using your RSS feed. 
If you like to, there is an additional field to deactivate the usage of cookies by Matomo.

Include Matomo Tracking, by Jonas Hellmann

This plugin lets you integrate your existing Matomo On-Premise into WordPress. If you don't already have a working Matomo (either On-Premise or M …

rbaer

This is a unofficial, basic WordPress plugin for the Matomo web analytics software platform. 
It adds the Matomo javascript code into every page of your website, so you don’t have to code PHP to add it to your templates.
It is based quite heavily on the (no more supported) Piwik Analytics WordPress plugin which itself is based on the (no more available) Google Analytics wordpress plugin by Joost de Valk.
The following options are supported:
<ul>
<li>matomo hostname</li>
<li>matomo path</li>
<li>site ID</li>
<li>option to control download tracking</li>
<li>option to exclude the admin user (probably you)</li>
</ul>
Please note, this plugin requires a self-contained Matomo installation somewhere under your control. It does not include Matomo itself.
See also <a href="https://matomo.org/" rel="nofollow ugc">The Matomo Website</a>.

Simple Matomo Tracking Code

This unofficial plugin adds the Matomo Web Analytics javascript code into the footer of your website. It has several useful options.

Include Matomo Tracking, by Jonas Hellmann vs Simple Matomo Tracking Code