How are job offers done?

Hi all last week I completed final rounds of interviews at Cambridge Associates and I was told I was a finalist and that I would be given an update this week. All communication has been done via email with HR thus far. Each day passed anxiously waiting and then today finally got an email saying I will be getting a call early next week with an update. Can anyone speak to what this may mean? This would be my first job so I don’t know how job offers are done. Are they ever done over the phone?
Any advice on what this may mean is greatly appreciated.