Ninja Forms is a popular contact form builder for WordPress websites. The advantages of using Ninja Forms include:

• Ease of Use: Users can create aesthetically appealing forms without requiring developer skills.
• Customizability: It offers a variety of templates, as well as the option to start with a blank form for full customization.
• Advanced Features: Ninja Forms supports various types of payments, including subscriptions, allowing for diverse form functionalities.

To install Ninja Forms on a WordPress site, follow these steps:

1. Go to your WordPress site admin and click Add New Plugin.
2. In the search bar, type Ninja form.
3. Click Install Now, then Activate.
4. Navigate to the Ninja Forms menu item and select Add New.
5. Choose a template or select a blank form to customize.
6. After customizing, click Publish.
7. Copy the shortcode of your form and embed it in your web pages by pasting the code into the shortcode widget of your page builder.

There are two methods for Ninja Forms tracking with Google Analytics 4 (GA4):

1. Automatic Form Tracking: This feature is provided by GA4 but isn't always reliable due to issues like false positives when users start filling out form fields or click submit without completing the form.

2. Google Tag Manager (GTM): A more robust method that involves using GTM to deploy a custom tag that pushes data into the Data Layer. This method is recommended for its reliability.

To create a Custom HTML Tag & Trigger for Ninja Forms tracking in GTM, follow these steps:

1. Use the provided jQuery code snippet to capture form submissions by listening for the nfFormSubmitResponse event.

2. In GTM, go to Tags → New, then click Tag Configuration and select Custom HTML. Paste the code snippet.

3. To trigger this tag, click the Triggering space and select All Pages for initial testing.

4. Name your tag descriptively and click Save.

5. Test the form by filling it out and submitting it, then check the results in GTM's Tag Assistant.

To send a GA4 Ninja Form Submission Event using GTM, you need to:

1. Create a GA4 tag similar to the Custom HTML tag, but choose Google Analytics: GA4 Configuration as the tag type.

2. Insert your GA4 measurement ID found under Admin → Data Streams in GA4.

3. Create a Custom Event trigger in GTM using the event name pushed into the Data Layer, such as ninja_form_submission.

4. If you have multiple Ninja Forms, you may need to create a Data Layer Variable to distinguish between them and refine your trigger accordingly.

5. Test the setup in GTM's Preview mode and ensure the tag fires correctly upon form submission.