If you happen to have gathered a lot of great reviews from direct bookings, Vrbo now provides the opportunity to leverage your reviews on their sites.
You cannot add reviews manually and push them to Vrbo. They have to be left on your Hostfully site by the guest after a direct booking. This is a requirement from Vrbo.
The feature is ON by default. If you want to deactivate, you can toggle OFF the "Synchronize Reviews" button on Vrbo channel management page, as below:
With this feature, your reviews will be synchronized to the Vrbo sites (their review crawler visits a couple of times a day and synchronizes new reviews), and will shortly be displayed on your listing pages, as below:
Note that the review will show the title, rating, date submitted, the stay date and will list your property management company as the source of the review.
Also by design, the reviews from Direct Bookings, once synchronized with Vrbo as above, can't be removed from Vrbo.
Airbnb reviews will be automatically imported to PMP property's Reviews tab upon property import or synchronization. However, these reviews are for internal use only, which hosts can respond to, and are not allowed to be exposed externally per Airbnb's policy.
See also the article on Capturing and Managing Reviews for more details about the topic.