Whereas quantitative research aims to develop objective theories by generating quantifiable numerical data, qualitative research aims to understand meaning. This might be the meanings that people attribute to their work, their behaviours or beliefs, or their attitudes or perceptions. Qualitative research is often based on methods of observation and enquiry; qualitative research “explores the meaning of human experiences and creates the possibilities of change through raised awareness and purposeful action” (Taylor & Francis, 2013). Qualitative research focuses on life experiences; they are more about the “why” and “how” rather than the “how many”, or “how often”. 

From https://deakin.libguides.com/qualitative-study-designs/about 

An oral history is a type of qualitative interview. Click the link to this guide to see tips for creating questions to ask your interviewee, along with ways to record and save your interview.