A data management plan is a formal document that outlines what you will do with your data during and after you complete your research. It describes the data that will be created, the standards used to describe the data (metadata), who owns the data, who can access the data, how long the data will be preserved (and/or made accessible), and what facilities and equipment will be necessary to disseminate, share, and/or preserve the data. Several funding agencies require or encourage the development of data management plans for research.
(Source: https://researchdatamanagement.harvard.edu/data-management-plans)