I wan’t to add data in a custom field that I created, I used InstallSchema like this: Setup/InstallSchema.php use MagentoFrameworkSetupInstallSchemaInterface; use MagentoFrameworkSetupSchemaSetupInterface; use MagentoFrameworkSetupModuleContextInterface; class InstallSchema implements InstallSchemaInterface { public function install(SchemaSetupInterface $setup, ModuleContextInterface $context) { $installer = $setup; $installer->startSetup(); $installer->getConnection()->addColumn( $installer->getTable('quote'), 'pakke_shipmentid', [ 'type' => 'text', 'nullable' => true, […]