Please, forgive me for the probably dumb question but this the first time I use Magento. I have been asked to make a simple change to an existing page (insert a few words of text). I have been granted access to the system through a web interface. After a couple of hours of "navigating" the Contents, I found that the page I need to access is activated by the following block
{{block class="Magento\Framework\View\Element\Template"template="Magento_Theme::storelocator/XXXXXX.phtml"}}
XXXXXX is a specific name that I prefer to anonymize. My questions are: How do I find the "real" code (the XXXXXX.phtml) file? Is it available and possibly editable from the same web interface? Or do I need to have the original file, modify it and upload (where in this case)? Thanks in advance for any help, Mario