To receive your clients’ feedback from Facebook, you can add a standard Facebook post widget or Comments widget.
To add a post from Facebook, click the post settings button on the right and select "Embed".
Facebook will provide you with a code that you can insert in the "Content" panel of the T123 block from the “Other” category and re-publish the page.
Learn more on embedding HTML in our guide: http://help.tilda.ws/html
There is also a SN601 block on Tilda that can be used for embedding comments (Blocks library → Social networks). It allows you to add comments from VK and Facebook at the same time.