External PHP file to create a downloadable text file

I am trying to create a button that triggers downloaded file filled with content from a PODS post type.

I have the following that downloads a txt file when a HTML button is click:

<?php //Generate text file on the fly

header("Content-type: text/plain");
header("Content-Disposition: attachment; filename=savethis.txt");
 
// do your Db stuff here to get the content into $content
print "This is some text...\
";
print $content;
?> 

But when I try to add something like $staff_social = pods(‘staff_member’, get_the_id()); I get an error:
Uncaught Error: Call to undefined function pods()

Is it possible to get PODS data with an external PHP file like this?

THanks