How to Send a Code 503 for WordPress

1. Access your WordPress Administration panel and click on 'Plugins' in the admin menu. The plugins page will appear, displaying your installed plugins.
2. Click the 'Add New' button. Type 'Maintenance' into the search field to pull up a list of available maintenance plugins. Each of these plugins, when activated, will display a 'placeholder' page instead of your website that informs visitors that the site is unavailable.

3. Install either 'Maintenance Mode,' the 'Site Maintenance' plugin or 'ThemeFuse Maintenance Mode' by clicking the 'Install Now' link beneath the plugin name. These three plugins have been tested to provide the most consistent user experience and will allow you to access your WordPress site while enabled, if you log in as an Administrator. Both 'Maintenance Mode' and 'Site Maintenance' come with some default placeholder pages, but allow you to input your own HTML. 'ThemeFuse Maintenance Mode' provides a pre-designed module that you can configure with a message, email address and Twitter username.
4. Activate the plugin by accessing the Plugin settings link from your main Plugins page. In some cases, the plugin may activate automatically when installed, and no further activation is necessary. You must still visit the settings to configure the appearance and behavior of your '503' page.