Solution
Deploy the following code on a Suitelet:
function renderPDF(context){
var serverResponse = context.response; //Gets the response object
var testData = 'TEST BODY'; //Test string to be rendered as PDF
var filename = 'PurchaseOrder_123456.pdf'; //Sample File name to be set when downloaded
serverResponse.setHeader({
name: 'Content-disposition',
value: 'filename="' + filename + '"',
}); //sets the filename to the specified format or name
serverResponse.renderPdf({
xmlString: testData
}); //renders the string as a PDF file
return;
}