Guidance Clarity Act of 2020 This bill requires federal agencies to state on the first page of guidance documents that such guidance (1) does not have the force and effect of law, and (2) is intended only to provide clarity to the public about existing legal requirements or agency policies. Excluded from this requirement is guidance directed to the issuing agency or other agency that is not intended to have a substantial effect on the behavior of regulated parties, as well as internal executive branch legal advice or opinions addressed to executive branch officials.