Auto populate selected fields names

Hi Everyone, I want to insert the field name of the selected field which is decision field in subform in CRM from creator. I want to insert the value each value have a separate row in subform
I have form in Zoho Creator, and it's have a associated Deal in CRM.
And it contains 20 decision fields.

in my Deals Module I have a subform name Document_Required and it contains Document_Name field which is Single line.

Now, I want to populate the field names of the ticked of selected decision fields from my form in Zoho Creator, to subform in the Deals Module.

I contained the field names into variables.

example:

response = zoho.crm.getRecordById("Deals",deal_id);

previous_subform = response.getJSON("Document_Required").toList();

getdocument = previous_subform.getJSON("Document_Name");

if(input.Decision1 == true)
{

field1 = "Decision1";

}

if(input.Decision2 == true)
{

field1 = "Decision2";

}

createmap =Map();

createmap.put("Document_Name",field1);

createmap.put("Document_Name,field2);

createmap.put("Document_Name",field3);

data = List();

data.add(createmap);
response2 = zoho.crm.updateRecords("Deals",deal_id,data);

this is not working