Authentication Of Morgan Silver Dollar What Is A Certificate Of Authentication For A Painting?

What is a Certificate of Authentication for a painting? - authentication of morgan silver dollar

I have a picture that is on sale for a famous artist. I do not know if it really painted by the artist. The box is authenticating with a certificate. What does this mean? Does this guarantee either an artist or you may not even be for her? Authentication certificates generally true or not? Thanks for any help.