in vk.com/dev/video.Search I have it

When I call the API, I have this, the property “Files” does not exist

Answer 1, Authority 100%

in the documentation by the video.search in the column Result said:

If your application uses direct authorization , returns
Additional field Files , containing a link to a video file (if
The roller is posted on the VKontakte server) or a link to the external resource
(if the roller is built with any video hosting).

I guess you do not have the ability to use direct authorization, because quote ):

Access to this type of authorization can only be obtained after
Preliminary approval with the administration of VKontakte.