How To Force Two Factor Authentication in WordPress with Jetpack

What is Two Factor Authentication? Two-factor authentication is a process involving two stages to verify the identity of an entity trying to access services in a computer or in a network. In this case the second state is confirming your identity by entering a unique code sent to your cell phone via SMS when logging into your WordPress website.
Why should I use Two Factor Authentication?
To significantly increase the security of your WordPress website.
How to force Two Factor Authentication in WordPress with Jetpack
Sign up for a WordPress.com account if you don’t have one already
Login to your WordPress.com account and navigate to Profile > Security > Two-Step Authentication or just click this link to see the following:
Click Get Started, enter your cell phone number and click Verify via SMS:
Enter the code that was texted to your cell phone and click Enable:
Save the listed Backup Codes somewhere safe, check I have printed or saved these codes click All Finished!
Install and enable the Jetpack by WordPress.com WordPress plugin
In your site’s WordPress admin dashboard navigate to Jetpack > Settings > Security, then toggle on the Single Sign On feature
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Source: https://managewp.org/articles/14804/how-to-force-two-factor-authentication-in-wordpress-with-jetpack

source https://williechiu40.wordpress.com/2017/04/07/how-to-force-two-factor-authentication-in-wordpress-with-jetpack/