I don't know what the document is for, but you may need an apostille if you plan to use that document in China.

https://www.dos.pa.gov/OtherServices/Certifications_Apostilles/Pages/How-Do-I-Obtain-an-Apostille-or-Certification.aspx#:~:text=Customers%20can%20have%20apostilles%20and,entrance%20of%20the%20Keystone%20Building.

A notary in the US only works as an official witness of a signature. Apostille verifies the document being signed.