The act of notarizing a document exists to add legal weight to a document by having a third party authenticate the signatures on it, according to Investopedia. Simply notarizing a document does not make it legally binding.
Notarizing a document does not make the provisions in it legal, according to the National Notary Association. The act of notarizing signifies that the persons involved were the ones who signed it.
Certain legal documents, such as power of attorney and deeds may require notarization, according to the association. Also, notarized signatures increase the veracity of other documents in court.
Parties can agree to abide by the contents of a notarized document in certain situations, such as custody agreements, but any party can challenge the agreement in court and effectively nullify it, according to Lawyers.com.