I was hired as an internal candidate, which they prefer over hiring external. The job process begins on sucessfactors as an online application. Once selected you'll be phone screened, then given a project pertinent to the current goals of WFM at the time (competitor opening, boosting basket size, increasing customer count, etc) and given a budget and a time frame. The interview is a panel interview, usually consisting of the Marketing team you'll eventually be running, the regional marketing coordinator, store team leader and store department leadership. They'll take turns asking you questions, and asking you about your project, vision, goals etc.
Be prepared to understand the company, the different departments, company values and programs, such as the Whole Planet Foundation, Whole Kids Foundation, etc.
Typical frame of interview:
Opening statement / introductions
Project
Panel questions
Closing statement