Magento 2 Adding Total Due and Total Paid to PDF order

Hi I am trying to add total paid and total due lines on my Magento PDF Invoice.

Firstly you have to create pdf.xml at path :

app\code\Pawan\PdfCustomiser\etc


  <?xml version="1.0"?>
   <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Sales:etc/pdf_file.xsd">
      <totals>
         <total name="total_due">
            <title translate="true">Total Due</title>
            <source_field>total_due</source_field>
            <model>Pawan\PdfCustomiser\Model\Sales\Pdf\Totaldue</model>
            <font_size>7</font_size>
            <display_zero>false</display_zero>
            <sort_order>750</sort_order>
         </total>
         <total name="total_paid">
            <title translate="true">Total Paid</title>
            <source_field>total_paid</source_field>
            <model>Pawan\PdfCustomiser\Model\Sales\Pdf\Totalpaid</model>
            <font_size>7</font_size>
            <display_zero>false</display_zero>
            <sort_order>700</sort_order>
         </total>
     </totals>
   </config>

Here, source_field: is the field name which you created as a field in order.
model: is the file in model in which you code to add field in totals.
font_size: default font_size is 7 you can change it.
display_zero: If you don’t want to display field if amount is 0 then set it to false, otherwise set it to true.
sort_order: sort order for the position of your field.

Now create file at path:  app\code\Pawan\PdfCustomiser\Model\Sales\Pdf\Totalpaid.php

<?php

namespace Pawan\PdfCustomiser\Model\Sales\Pdf;

class Totalpaid extends \Magento\Sales\Model\Order\Pdf\Total\DefaultTotal
{
    /**
     * @var \Magento\Tax\Model\Config
     */
    protected $_taxConfig;

    /**
     * @param \Magento\Tax\Helper\Data $taxHelper
     * @param \Magento\Tax\Model\Calculation $taxCalculation
     * @param \Magento\Tax\Model\ResourceModel\Sales\Order\Tax\CollectionFactory $ordersFactory
     * @param \Magento\Tax\Model\Config $taxConfig
     * @param array $data
     */
    public function __construct(
        \Magento\Tax\Helper\Data $taxHelper,
        \Magento\Tax\Model\Calculation $taxCalculation,
        \Magento\Tax\Model\ResourceModel\Sales\Order\Tax\CollectionFactory $ordersFactory,
        \Magento\Tax\Model\Config $taxConfig,
        array $data = []
    ) {
        $this->_taxConfig = $taxConfig;
        parent::__construct($taxHelper, $taxCalculation, $ordersFactory, $data);
    }

    /**
     * Check if tax amount should be included to grandtotals block
     * array(
     *  $index => array(
     *      'amount'   => $amount,
     *      'label'    => $label,
     *      'font_size'=> $font_size
     *  )
     * )
     * @return array
     */
    public function getTotalsForDisplay()
    {
//        $writer = new \Zend\Log\Writer\Stream(BP . '/var/log/pdftotalstotaldue.log');
//        $logger = new \Zend\Log\Logger();
//        $logger->addWriter($writer);
//        $logger->info("sdjkhsahda". $this->getSource()->getTotalPaid());
        $store = $this->getOrder()->getStore();
        
        if (!$this->_taxConfig->displaySalesTaxWithGrandTotal($store)) {
            return parent::getTotalsForDisplay();
        }
        $totalpaid = $this->getOrder()->formatPriceTxt($this->getSource()->getTotalPaid());
        
        $fontSize = $this->getFontSize() ? $this->getFontSize() : 7;

        $totals = [
            [
                'amount' => $this->getAmountPrefix() . $totalpaid,
                'label' => __('Total Paid') . ':',
                'font_size' => $fontSize,
            ],
        ];

        $totals[] = [
            'amount' => $this->getAmountPrefix() . $totalpaid,
            'label' => __('Total Paid') . ':',
            'font_size' => $fontSize,
        ];
        return $totals;
    }
}

same way new file Totaldue.php and small changes in place of $this->getSource()->getTotalPaid() replace with $this->getSource()->getTotalDue()

Next clear flush cache
after this your fields will be added in downloaded pdf of an order.