You can't. According to official website's information, Zhangchu.com is an online menu sharing platform, which provides some convenient and practical functions, such as searching for recipes, viewing the list of ingredients and purchasing ingredients. However, Zhangchu.com is not a specialized online shopping platform, and does not directly provide food purchasing services. Individuals can find their favorite recipes on online cooking websites, and then buy corresponding ingredients according to the recipes. If you want to provide food purchasing service on the online cooking website, you can find a nearby supermarket or food supplier on the website and then go to a physical store to buy the required ingredients.