How to check who create, modify the contact on the contact management

There would only be an event log record that would be created. If there was a property for the created or modified ID you'd see it in the API Documentation.

I would use global event handler and log the data you want into event log using API.

Hi Juraj,

It's right we would use the global event handler and log it but currently there are no global event handler manage in existing k11 code. And some anonymous activities observer in the contact management module so need to find that which user done the anonymous entries in the contact management.

Global event handlers are available in Kentico 11 too, just check the documentation. And if you see anonymous contacts, they are most likely generated automatically from the web site visitors. But the visitor did not provided any more details which could be filled in - like form submission or registration. I would recommend checking the online marketing documentation and how the contact recognition works.