@elmo.conroy
To set PHP headers in a .htaccess file, you need to use the Header directive. Here's how you can set some common PHP headers:
Make sure that the mod_headers module is enabled in Apache for these directives to work. You can usually enable it by adding LoadModule headers_module modules/mod_headers.so to your Apache configuration file or by using the a2enmod headers command (on Ubuntu/Debian).
Note: These directives will only affect PHP files. You can modify the file extension in <FilesMatch ".(php)$"> to target different file types, if needed.