This shows how to create a folder using SuiteScript
/**
 * @NApiVersion 2.x
 * @NScriptType UserEventScript
 * @NModuleScope SameAccount
 */
define(['N/record'],
/**
 * @param {record} record
 */
function(record) {
    function afterSubmit(scriptContext) {
        var objRecord = record.create({
            type: record.Type.FOLDER,
            isDynamic: true
        });
        
        objRecord.setValue({
            fieldId: 'name',
            value: 'Create Folder Test'
        });
    
		var recordId = objRecord.save({
			enableSourcing: true,
			ignoreMandatoryFields: true
		});
    }	
    
    return {
        afterSubmit: afterSubmit
    };    
});