Follow these two steps:
If you are signing in as an AWS root account, sign in as usual with your user name and password when prompted. To sign in as an IAM user, use the account-specific URL and provide your user name and password when prompted.
If you have enabled virtual, hardware, or SMS MFA, enter the six-digit MFA code that appears on your MFA device. If you have enabled U2F security key, insert the key into the USB port of your computer, wait for the key to blink, and then touch the button or gold disk on your key.
