By default, some of our themes come with a support for Jetpack testimonials, so there is no need to enable it in the Jetpack settings. There are some cases when the theme support is ignored.
In this case, you’ll need to use Jetpack settings: go to Jetpack → Settings → Writing in your WordPress Dashboard and toggle on the Testimonials option under Custom Content Types.
You can add testimonials easily by going to Testimonials → Add New in your WordPress Dashboard.
All testimonials are displayed in a testimonial archive page which is automatically generated by WordPress. The testimonial archive page can be found at http://yoursite.com/testimonial/ (replace http://yoursite.com/ with your own site URL).
Please note: the URL for the testimonial archive page must end with /testimonial/ (as shown in the example above) for the page to display testimonials properly.
You can add the testimonial archive to the Custom Menu, using a custom link.