People interested in contacting Michelle Obama can write to her by mail, phone the White House, or even tweet her Twitter account, @MichelleObama. All methods will probably result in responses from Michelle Obama's staff rather than Michelle Obama herself.
The White House's contact information is listed under the Get In Touch With Us link near the bottom of the WhiteHouse.gov home page. The website suggests using standard letter-size paper for written letters, and asks writers to include their return address at the top-left corner of the letter's envelope.
The main White House switchboard number is 202-456-1414. Letters for Michelle Obama should be addressed to:
The White House
1600 Pennsylvania Ave. NW
Washington, DC 20500