The 19th Amendment was not signed by the President. According to the Constitution of the United States, in order to amend the Constitution, two-thirds of Congress must vote in favor. Then, three-quarters of the states in the union must ratify the amendment, which occurred on Aug. 18, 1920.
Although it was not signed by President Woodrow Wilson, he was a staunch supporter, pressuring Congress and calling for a special session to see the amendment proposed to the states.
The 19th Amendment extends and secures the right to vote for all women. The women's suffrage movement began long before that, in July of 1848 at the Seneca Falls Convention, where advocates brought forward the first official demand for women's suffrage.
Susan B. Anthony and Elizabeth Cady Stanton drafted what would become the 19th Amendment in 1878, although neither lived to see it ratified.