How can I connect my hp printer to my iPad?

Is it one of the HP printers that support AirPrint ? If so then it just needs to be on the same wifi network as your iPad - there is info on AirPrint and the models that support it here. If it's not one of those models then HP also have their own ePrint app, or there are third-party printer apps such as Print Central For iPad and Print n Share which might work with it.

iOS AirPrint Printers
http://support.apple.com/kb/HT4356

How to Print from Your iPad: Summary of Printer and Printing Options

http://ipadacademy.com/2012/03/how-to-print-from-your-ipad-summary-of-printer-an d-printing-options

Print from iPad / iPhone without AirPrint

http://ipadhelp.com/ipad-help/print-from-ipad-iphone-without-airprint/

How to Enable AirPrint on a Mac and Use Any Printer

http://ipadhelp.com/ipad-help/how-to-use-airprint-with-any-printer/

 Cheers, Tom 😉