Answer: June 4, 1919
Explanation: Women fought to get the right to vote for almost 100 years and even some men helped along the way by like doing protests and starting the National Woman Suffrage Association by Susan B. Anthony and Elizabeth Candy Stanton. The First Women's Right Convention in Seneca Falls, NY which was organized by Susan B. and Elizabeth C. sparked the NWSA. After fighting for women's right to vote the 19th Amendment signed the law after passing through the House and Senate.
Fun Fact: The president during that time (Woodrow Wilson) supported the movement by supporting the Constitutional Amendment.
Hope someone learned something new :)