by Alexandre Froger on WordPress.org

Two-Factor Authentication Form
Add Two-Factor Authentication, Passwordless Authentication and Account Validation to your WordPress website.
This plugin adds the following major features to WordPress:
OTP Authenticator is regularly updated, and bug reports are welcome, preferably on Github, especially for advanced troubleshooting.
Each bug report will be addressed in a timely manner, but general inquiries and issues reported on the WordPress forum may take significantly longer to receive a response.
Only issues occurring with included integrated plugins (or plugin features), core WordPress and default WordPress themes (incl. WooCommerce Storefront) will be considered without compensation.
Troubleshooting involving 3rd-party plugins or themes will require compensation in any case, and will not be addressed on the WordPress support forum.
Although OTP Authenticator is designed to work out of the box with most combinations of WordPress plugins and themes, there are some edge cases necessitating integration, with code included in the core files of OTP Authenticator executing under certain conditions.
Integrations added to core are limited to popular plugins and themes: any extra code specific to a handful of installations require a separate custom integration plugin not shared with the community (decision at the discretion of the OTP Authenticator plugin author).
If such need for plugin integration arises, website administrators may contact the author of OTP Authenticator to become a patron.
All integrations are to be funded by plugin users, with downpayment and delivery payment, at the plugin author’s discretion, without exception.
The patron in return may be credited with their name (or company name) and a link to a page of their choice in the plugin’s Changelog.