@Eulogio Gallo
If you want to edit /create/delete custom metadata then you have need to use Metadata api.
Custom metadata rows resemble custom object rows in structure. You create, edit, and delete custom metadata rows in the Metadata API or in Setup. Because the records are metadata, you can migrate them using packages or Metadata API tools.
Custom metadata records are read-only in Apex and in the Enterprise and Partner APIs.
It is not possible to insert test custom metadata, unless you use the Metadata API which would also present a challenge in a test scenario.
