php-require | PHP Class that provides a nodejs style module loader

Whening outputting a PDF to a webpage you cannot output anything before it as it has to set the HTTP headers. The PHP headers function cannot set them if there is anything on the screen.

From the docs https://www.php.net/manual/en/function.header.php:

Remember that header() must be called before any actual output is sent, either by normal HTML tags, blank lines in a file, or from PHP. It is a very common error to read code with include, or require, functions, or another file access function, and have spaces or empty lines that are output before header() is called. The same problem exists when using a single PHP/HTML file.

Just as an extra note, you can include TCPDF through composer using tecnickcom/tcpdf as it looks like you are probably already using composer with either symfony or laravel as you are using the dd method.

Note that TCPDF doesn't throw exceptions as well. If you want it to throw exceptions you can overwrite the error method. E.g.