What are the requirements in getting a China visa? a friend is inviting us too visit her in Henan

If you are invited by someone, you need to provide an invitation letter with a copy of the inviter's valid Chinese residence visa and passport information page of inviter's; or Chinese national identity card if she is a Chinese.
The visa typr should be tourist L visa, other requirements for China visa can be found on following page: https://www.travelchinaguide.com/embassy/visa-application-philippines.htm