Unfortunately it's not possible to manage field level formatting with a QlikView or Qlik Sense Pivot Table since the entire chart is exported from Qlik Sense (or QlikView) as is rather than the individual fields within the pivot table.
To work around this:
In QlikView/Qlik Sense, create a clone/copy of your original pivot table and convert the copy to a straight table.
Save your Qlik Sense or QlikView app, reload the NPrinting meta data so that the new cloned, newly created or copied straight table chart is available to NPrinting
Use the straight table chart, now visible to NPrinting after the metadata reload, to create a Pivot Table with QS or QV data by following the instructions one of the links below:
This approach is common when it is necessary to have a greater level of control of field level formatting as a report developer. This when permissions to format the source pivot table in Qlik Sense or QlikView are limiited or simply require a separate pivot view that is different to the QV or QS chart without changing the source chart.