IF you are conducting an oral history interview for a class assignment, and your professor does not want the interview(s) saved, you do NOT need a consent form.
IF you are conducting an interview to be saved and sent to a repository, you will need a consent form. Consent forms are extremely important for oral history interviews - they determine and assign copyright and access rights. The Hood College Archives consent form above is provided to you as an example. There are other examples available on the internet and from books on oral histories.