There is a site on DLE
Have a retailCRM
How to link them together so that when filling out a form on the website(DLE) the task automatically appears on retailCRM
The finished code is unlikely to be provided by someone.And the answer is simple - see their API, and in DLE, see the implementation of sending data to this API when filling out a form.
At a minimum, you need to write an integration for DLE using the provided API.