Hello,
Please note that PHP 8.3 was released after phpdocx 13, so this version has not been tested with PHP 8.3. phpdocx 13 is compatible from PHP 5.6 to PHP 8.2.
PHP 8.3 doesn't include breaking changes from PHP 8.2. You can test if the phpdocx 13 code you are using works with PHP 8.3 and also check your server logs to find if some PHP error appear.
Our recommendation is using phpdocx 14.5 with PHP 8.3.
Regards.