Walmart is not a franchise organization. All of the stores are owned and operated by the parent company.
Franchise organizations allow investors and entrepreneurs to open a store using their brand and processes. It provides an opportunity to gain equity in a brand and secure a share in a business that could already have momentum in the market. Often times, this is more appealing for business people as it requires less work to open a franchise than their own company. A new company would require significant investment in order for it to get up and running, and the return may take a long time to realize.