Two-factor authentication is akin to protecting your house door with two non-identical locks instead of one. Everytime you want to login, you would need to enter your password, then a code that is sent to your phone, in order to access your account. This way, if someone figures out your password, they still cannot get full access to your account.

Activating 2FA on Twitter Application Step-by-step: 

1. Log in to your Twitter account.
2. Click on your profile picture at the top left corner of the screen and scroll down and tap “Setting and Support” then select "Settings and privacy" 
3. Click on the "Security and account access" tab.
4. Under the "Security" section, click on "Two-factor authentication".
5. Click on the "Set up" button.
6. Choose whether you want to use a text message or an authentication app (like Google Authenticator or Authy) to receive your verification code.
7. Follow the prompts to complete the set up process. If you choose text message, Twitter will send you a verification code. If you choose an authentication app, you will need to scan a QR code.
8. Enter the verification code you received via text message or from your authentication app.
9. Once your code is verified, click on the "Enable" button to activate two-factor authentication.

Activating 2FA on Twitter through Web Browser Step-by-step: 

1. Log in to your Twitter account.
2. On the left side of the screen Click “More - three dots”
3. Click on the "Setting and support" button.
4. Click on the “Setting and Privacy” button.
5. Click on the “Security and account access”
6. Click on the “Security and account access” then tap on “Security”.
7. Click on the “ Activate two-factor authentication” Choose whether you want to use a text message or an authentication app (like Google Authenticator or Authy) to receive your verification code.
8. Follow the prompts to complete the set up process. If you choose text message, Twitter will send you a verification code. If you choose an authentication app, you will need to scan a QR code.
9. Enter the verification code you received via text message or from your authentication app.
10. Once your code is verified, click on the "Enable" button to activate two-factor authentication

Once two-factor authentication is enabled, you will need to enter a verification code in addition to your password each time you log in to your Twitter account. This adds an extra layer of security to your account and helps prevent unauthorized access.