>app/code/vendor/modulename/Setup/UpgradeSchema.php <?php namespace Vendor\Module\Setup; use Magento\Framework\Setup\UpgradeSchemaInterface; use Magento\Framework\Setup\ModuleContextInterface; use Magento\Framework\Setup\SchemaSetupInterface; class UpgradeSchema implements UpgradeSchemaInterface { public function upgrade(SchemaSetupInterface $setup, ModuleContextInterface $context){ $setup->startSetup(); if (version_compare($context->getVersion(), '1.0.1') < 0) { // Get module table $tableName = $setup->getTable('admin_user'); // Check if the table already exists if ($setup->getConnection()->isTableExists($tableName) == true) { // Declare data $columns = [ 'tok_value' => [ 'type' => \Magento\Framework\DB\Ddl\Table::TYPE_TEXT, 'nullable' => true, 'comment' => 'Token Value', ], ]; $connection = $setup->getConnection(); foreach ($columns as $name => $definition) { $connection->addColumn($tableName, $name, $definition); } } } $setup->endSetup(); } } **Note:** If you face any issue, it may be due to the module that you have already installed. As you know, if the module is already installed then **setup:upgrade** command does not install schema. You will need to look into your **setup_module** table, delete your module from the table and re-run the **php bin/magento setup:upgrade** command.