For this tutorial, we’ll be using the Ninja Forms plugin.
The first thing you need to do is to install and activate the plugin. For detailed instructions, see this page.
After you’ve installed the plugin, you need to build your form, a complete documentation can be found in this page.
On the Ninja Forms Dashboard, note that each of your Ninja Forms have a unique shortcode.
In our case, the shortcode is:
[ninja_form id=1]
From the Appearance menu on the left-hand side of the Dashboard, select the Customize option to bring up the Customizer, then click on the Listing details section.
Past your shortcode to Enquiry form shortcode input box.
Click the Publish button.
That's all.