when did communist started to come to Vietnam? year & date?

Answer 1

"Ho Chi Minh was born, as Nguyễn Sinh Cung, in 1890 in Hoàng Trù Village (his mother's hometown). From 1895, he grew up in his paternal hometown of Kim Liên Village, Nam Đàn District, Nghệ An Province, Vietnam."

[...]

"From 1919-1923, while living in France, Ho Chi Minh embraced communism. Following World War I, under the name of Nguyễn Ái Quốc (Nguyen the Patriot), he petitioned for equal rights in French Indochina on behalf of the Group of Vietnamese Patriots to the Western powers at the Versailles peace talks, but was ignored. Citing the language and the spirit of the U.S. Declaration of Independence, Ho petitioned U.S. President Woodrow Wilson for help to remove the French from Vietnam and replace it with a new, nationalist government. Again his request was ignored."

"Ho Chi Minh soon helped to form the French Communist Party and spent much of his time in Moscow afterwards, becoming the Comintern's Asia hand and the principal theorist on colonial warfare. It was at this time that Nguyễn Ái Quốc took the name of "Hồ Chí Minh" ("the one who is enlightened")."

Answer 2

Well, the communists didn't really start coming to Vietnam. Ho Chi Mihn was a communist living in Vietnam who asked the U.S. for help in obtaining Vietnamese independence from France. The U.S. ignored H.C.M. and so he turned to the Chinese Communist for help because they shared an ideology.