Navigate to the Yahoo! Mail login page in any browser.
Under the sign-in area in the top-left corner of the screen, click "Sign Up."
Fill out the sign-up form with your name, gender, birth date, country and postal code.
Choose an ID name from the suggestions listed. If you don't like the suggestions, type in an alternate. Yahoo! checks to see if that ID is taken. If it is, add a number or letter or choose a completely different ID. Once the ID name is chosen, enter a password and retype the password.
Give Yahoo! an alternate email in case you forget your ID or password. Choose a security question and answer when prompted to do so.
Congratulations, you have a Yahoo! Mail account. Yahoo displays a page that shows your account details and sends a confirming email to your alternate email address. You are redirected to your inbox page, where you can personalize options for your account.