Hi Taehyung,
The short answer:
Archival descriptions are metadata about records - they describe the holdings of your institution. Researchers and community members use your archival descriptions to discover what kind of content they will find in your holdings.
Donors are associated with accession records - Donor records are a way of managing information about those who have given records to the institution, whether by deed, gift, transfer, purchase, or otherwise. Because they contain personal information (such as contact information), they are not made available to public users.
For more details, see: