2-step verification needs to activate from Admin console first :

Enable 2-Step Verification for your domain

  1. Sign in to the Google Admin console.
  2. Click Security > Basic settings.
    Where is it?
  3. Under 2-Step Verification, check Allow users to turn on 2-factor authentication.

This makes 2-Step Verification available for your users, but does not automatically enroll them. To enroll, users need to configure their verification settings individually.

Turning on 2-Step Verification (For User)

  1. Sign in to your Google Account settings page by clicking on your name or picture in the upper right corner of the screen and then clicking Account.
  2. Scroll down to the "Signing in" box.
  3. Click 2-Step Verification. This will bring you to the 2-Step Verification settings page.
  4. You will then see a step-by-step guide which will help you through the setup process.
  5. Once you’re done, you’ll be taken to the 2-Step Verification settings page again. Be sure to review your settings and add backup phone numbers.
  6. You’re done! Next time you sign in, you’ll receive an SMS with a verification code

Note: You also have the option of using a Security Key for 2-Step Verification.

Turning off 2-Step Verification (For User)

  1. Log in to particular account Visit the Using 2-Step Verification page under your Google Account settings. Sign in with your username, password, and verification code if prompted.
  2. Click Turn off 2-Step Verification.
  3. A pop-up window will appear to confirm that you want to turn off 2-Step Verification. Click OK.