Field Selector Tab
In the Field Selector tab, you can retrieve the leads by selecting the fields that you want. In the Retrieve activity, the Field Selector tab only supports Retrieve Lead by Id, Retrieve Multiple Leads, Retrieve Multiple Leads by List, and Retrieve Lead Changes APIs.
You can choose the fields that you require by selecting the check box on the left of the panel. Or you can choose all of the fields by clicking Select All in the upper-left corner of the panel.