Well as a rough outline you would need to:
Buy the commercial PDFJet library (around $300 IIRC)
Buy a licence for Palatino Linotype font from Linotype.
Using the
jPDFJet library you would load the font and embed it in the PDF.
If you don't embed the font then anyone who doesn't have that font loaded on their device will see it a substituted font in the PDF instead of Palatino.