Promoting Accountability and Security in Transitions Act of 2020 or the PAST Act This bill revises requirements for preservation of presidential records and requires that information be made available to the next administration in a timely fashion. Specifically, the bill (1) requires the President to receive written guidance from the National Archives and Records Administration (NARA) before destroying any records, (2) prohibits White House staff from using nonofficial electronic messaging accounts that cannot be easily copied or forwarded to official accounts, (3) establishes consequences for former Presidents who destroy presidential records, (4) requires former Presidents to cover the cost of digitizing records for display in a presidential library, and (5) requires NARA to ensure that newly inaugurated Presidents are granted easy access to national security information.