References for work experience - please answer my humble question

Dear Charterholders,

Would someone please enlighten me about the process of getting the references?

  1. Do I need to ask 3 supervisors, or can they be peers in my job?

  2. What questions do they have to answer in order to provide the appropriate reference?

Reason I’m asking: I will have to reach back to employers before 2014, so I want to explain as clearly as possible what reference I require.