RANCHO PALOS VERDES, Calif. – Hewlett-Packard Co. will soon include its webOS system for smartphones on all its PCs, upcoming tablet computer and higher-end printers, putting it in competition with operating software from Apple, Google and Microsoft.

HP’s intentions, laid out at a prominent technology conference Wednesday, represented a particular challenge to longtime partner Microsoft Corp., whose Windows operating system runs on all of the 65 million PCs that HP shipped last year.

CEO Leo Apotheker said the company should have put webOS further into the marketplace sooner. HP acquired webOS when it bought struggling cellphone maker Palm Inc. last year.

HP’s interest in spreading webOS lies in making sure phones and PCs work seamlessly together — like Apple’s Macs and iPhones. HP also wants to make sure it has a foothold in the fast-changing mobile software market.