How do I convert my submitted form uploads as one pdf and send that as an attachment to receiver in laravel?

A Laravel 5.7 project

I have a form where I need to upload 3 images and 2 pdfs in single form.

What I am going for:

1. Submit the form and save data.
2. Convert the files uploaded via the user form as a single pdf.
3. Sending the converted pdf as a mail attachment using code.

Tried like this

public function sendmail(Request $request){
        $data["email"]=$request->get("email");
        $data["client_name"]=$request->get("client_name");
        $data["subject"]=$request->get("subject");

        $pdf = PDF::loadView('mails.mail', $data);

        try{
            Mail::send('mails.mail', $data, function($message)use($data,$pdf) {
            $message->to($data["email"], $data["client_name"])
            ->subject($data["subject"])
            ->attachData($pdf->output(), "invoice.pdf");
            });
        }catch(JWTException $exception){
            $this->serverstatuscode = "0";
            $this->serverstatusdes = $exception->getMessage();
        }
        if (Mail::failures()) {
             $this->statusdesc  =   "Error sending mail";
             $this->statuscode  =   "0";

        }else{

           $this->statusdesc  =   "Message sent Succesfully";
           $this->statuscode  =   "1";
        }
        return response()->json(compact('this'));
 }

via Chebli Mohamed