How to embed custom code for salesforce integration

my question was i need to integrate Salesforce Web-To-Lead functionality through my contact us page but when i made changes in contact us page form according to salesforce Web-to-Lead functionality. when i am trying to imbed that code through GitHub repository through script tag the functionality doesn’t work in salesforce can anyone provide me a solution on this. or how can i achieve it. NOTE : functionality is working on live server but after imbedding that code in webflow contact us page its not working.

Here is my site Read-Only:
(how to share your site Read-Only link)