Before previewing the Testimonials, you will need to add it to your Checkout page in Checkout editor. Please go to the your theme customization and follow our steps to add Testimonials.
- Step 1: Choose Checkout page > Choose Add app block > Select Extra Widget.
- Step 2: Choose Testimonials in Extra widget type option.
You can also remove this feature by clicking on the bin icon at the bottom right and change the position of this Testimonial by holding the item and dragging it to the place you want.