Aaron D. Campbell

Sometimes it’s a private blog, and that’s all there is to it. If all you want 
to do is limit your blog to only registered users, look no further. Simply 
install this plugin, and stop worrying.

Authenticate

Instantly requires that users be logged in to visit your site. Also serves as a good base for expansion. No interface, just activate and go!  Requires …

oskarhane

This plugin makes WooCommerce’s login form compatible with the <a href="https://wordpress.org/plugins/two-factor-auth/" rel="ugc">Two Factor Auth plugin</a>. It simply adds a field for an One Time Password to WooCommerce’s login form.

Two Factor Auth for WooCommerce

Adds a field for a One Time Password to WooCommerce's login form.

Authenticate vs Two Factor Auth for WooCommerce