Yes, you have to serve the papers on the landlord and also on HPD.
The judge or the clerk will explain to you how to serve the papers. Follow the instructions carefully and keep your proof. You might have to send the papers by certified mail, return receipt requested and regular mail. The receipt is your proof that the papers were mailed.
If you do not serve the landlord the right way, the judge may dismiss the case and you will have to start over.