What is the role of a University Archivist I am wanting to know roughly what it is a university archivist does,
and what sorts of documents are in the collections they manage.

An acceptable answer would be "It varies wildly from institution to institution",
if indeed that is the case.
On the other hand, perhaps it is a very consistent position, with well understood tasks and duties.
In general, an archivist is someone who preserves records and artifacts of the university's historical record. The part that probably varies from institution to institution is which objects are retained.

For instance, some might keep minutes of board of trustee meetings, letters to the president or chancellor, and other records, while others may choose not do so.

As a further example, the Yale University archivist has the following responsibilities:


Works with the schools, departments, and offices of the university to appraise the records that they create in the course of their activities and to select those that need to be preserved for future use;
Works with students, alumni, faculty, and friends of the university to collect papers, graphic materials, audio recordings, and objects that document Yale life and history;
Promotes, supports, and sponsors programs and activities that contribute to accessible information, interpretations, and research on Yale history.