COVID Preparedness, Response, and Effective Planning for Advanced Requirements by the Executive Branch Act of 2021 or the COVID PREPARE Act of 2021 This bill requires federal agencies to submit to Congress plans for responding to COVID-19 (i.e., coronavirus disease 2019). Specifically, each agency shall submit (1) an initial report detailing an action plan, informed by research and best practices learned from the onset of COVID-19, previous pandemics, and health emergencies, for addressing the needs and mitigating and eliminating the risks and challenges associated with COVID-19 and the deployment of COVID-19 vaccines; and (2) subsequent reports, on a quarterly basis until the President ends the declared emergency, that update the details submitted in the plan. The initial report shall include agency priorities for preparing for and responding to the pandemic, including continuity of operations and fulfilling the agency's mission and priorities related to the deployment of COVID-19 vaccines; measurable goals specific to priorities and a time line for addressing each priority; anticipated challenges to addressing priorities and how the agency will address such challenges; how the agency will consult with Congress, the public, state and municipal governments, and relevant stakeholders while working remotely; how the agency plans to issue relevant guidance to entities under the jurisdiction of the agency; and any resources the agency needs from Congress.