To add a form to a page you can either add it to an existing page or by creating a new page.
Adding the form
Method 1: “Add Form” Button
When you edit a Page or Post, there will be an “Add Form” button above the editor.
Method 2: Form Shortcodes
On the Ninja Forms Dashboard, note that each of your Ninja Forms has a unique shortcode.
Within your page or post editor, you can insert the shortcode of your Ninja Form in order to embed it within your page or post.