How to insert integration code for CRM?

Option 1

Create a custom template for your landing page:

 /**
 *  Template Name: My landing page
 *
 */

and add the code manually as you would add to a static site.

Option 2

Create a custom field for your code on the landing page and output the meta content in the template created above.

Option 3

Write a conditional statement in your header file testing for the landing page and insert the snippet.

if (is_page( 'Landing Page' )) {

//do stuff