Besides 11 teams from Southeast Asia, Australia will play in the tournament for the first time, and there will be two groups of six teams each.
Vietnam are placed in the tough group A along with Malaysia, Thailand, Cambodia, Singapore, and Australia, while group B has Myanmar, Indonesia, Laos, Timor-Leste, the Philippines, and Brunei DS.
Vietnam's first match will be against Malaysia on August 6.
Malaysia won the annual tournament in 2018 in Indonesia, when Vietnam stopped at group stage.
Vietnam finished third at the U22 AFF Championship in Cambodia last month, and won the 2018 AFF Championship trophy at home.