Mark Field in List as editable

Hi there, how can i mark a field in a list as editable.

See this example.
https://snippet.dhtmlx.com/w2cdossn?_ga=2.18013626.2079692566.1629085584-110508645.1620638777

There sould be an Icon for example that user knows, that he can edit and select “Owner” with a double-Click.

You may add the icon to your column cells using the templates: