what authorized travel agency is stated in the requirements in tourist visa application?

I want to know what are the authorized travel agency that should provide the invitation letter of an applicant of china tourist visa. Because I have already the invitation letter came from Philippine Consulate in Guangzhou China to invite my sister in-law to pay us a visit here with my wife,her sister in Dongguan China
Is this useful enough to present in china embassy in manila for the applicant not need to present the said statement of account, bank account and ITR?