Hi, im a philippine passport holder and currently stay and work in sabah. im plan to visit friends in china, Im wanna ask how to apply visa to china?

You can ask a tour agency to help you to do it in Kuala Lumpur, but make sure to provide enough documents for them to do it.
You need to provide your passport, the application letter with recent taken photo, your invitation letter, your working permit in Malaysia for the tour agency. If you are the first time to go to China, you may need to provide 6-month bank statement, BIR-stamped income tax return form, working certificate from your company or professional ID.