McDonald's Corporation is an American multinational fast food chain, founded in 1940 as a restaurant operated by Richard and Maurice McDonald, in San Bernardino, California, United States. They rechristened their business as a hamburger stand, and later turned the company into a franchise, with the Golden Arches logo being introduced in 1953 at a location in Phoenix, Arizona. In 1955, Ray Kroc, a businessman, joined the company as a franchise agent and proceeded to purchase the chain from the McDonald brothers. McDonald's had its previous headquarters in Oak Brook, Illinois, but moved its global headquarters to Chicago in June 2018.

McDonald's is the world's largest fast food restaurant chain, serving over 69 million customers daily in over 100 countries in more than 40,000 outlets as of 2021. McDonald's is best known for its hamburgers, cheeseburgers and french fries, although their menu also includes other items like chicken, fish, fruit, and salads. Their best-selling licensed item are their french fries, followed by the Big Mac. The McDonald's Corporation revenues come from the rent, royalties, and fees paid by the franchisees, as well as sales in company-operated restaurants. McDonald's is the world's second-largest private employer with 1.7 million employees (behind Walmart with 2.3 million employees). As of 2022, McDonald's has the sixth-highest global brand valuation.

McDonald's has been subject to criticism over the health effects of its products, its treatment of employees, and other business practices.
Based on the reference text about McDonalds, tell me what year it was founded, how many daily customers they have, and their best selling product.
McDonalds was founded in 1940 and serves over 69 million customers a day as of 2021. It's best selling product are their french fries.