ot_typo3/ot_templating/Configuration/TCA/Overrides/pages.php

<?php
defined('TYPO3_MODE') or die();

// ** Add fields to the backend
$columns = array (
    'tx_opentalent_structure_id' => array (
        'label' => 'Id de la structure',
        'config' => array (
            'type' => 'input',
        )
    ),
);

\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addTCAcolumns(
    'pages',
    $columns
);

\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addToAllTCAtypes(
    'pages',
    'tx_opentalent_structure_id',
    '',
    'after:subtitle'
);