We can easily add article menu type to menu in Joomla first Log into your Joomla administrator panel Dashboard. Go to Menus which is appearing at the top menus hover over the menu link and then click AddNewMenuItem.
Then click select which is next to MenuitemType and then under the article heading title click single article a new page appears where we need to type a title of menuitem.Next to select article,click change/select.
There is filter facility at the top which finds your article and then click on article title. Once fills all the information required click save and close.
Now this menu will show on your front end website.Once click that menu link that article which is assigned to menu link display on website.