Question: where to find wps pin on hp officejet pro 8720?
Answer: From printer control panel screen, Go to. >> Setting >> Network Setup >> Wireless Settins >> Wi-Fi Proctected Setup >> PIN/Push button. ... 
Setup using network SSID steps following below documents. http://support.hp.com/us-en/product/HP-OfficeJet-Pro-8710-All-in-One-Printer-series/7902014/document...