title: Magento 2 - Edit Invoice PDF in a custom theme
body: <p>I want to edit the printable PDF invoice in Magento 2. To do this, I need to edit: </p>
  
  <pre><code>vendor/magento/module-sales/Model/Order/Pdf/AbstractPdf.php
  </code></pre>
  
  <p>But, what is the path I need so it does not get overridden during upgrade. I know the path should be something like this (but i cant figure it out):</p>
  
  <pre><code>/app/design/frontend/Vendor/Theme/Magento_Sales/ ? / ? / AbstractPdf.php
  </code></pre>
  
  <p>With templates, I know the path is /template/...but this is a Model - so Im not sure I know how that works. </p>