The Canary Islands are part of Spain, but not part of the EU VAT zone. Instead of VAT (IVA), the islands apply their own local indirect tax called IGIC – generally 7 %, and in many B2B cases 0 %.
This means that invoices issued to customers based in the Canary Islands must not include standard Spanish VAT. Depending on the business relationship, they should either apply IGIC or be issued without any VAT at all, following the special tax status of the islands.
Take into account that the reverse charge mechanism doesn't apply here. Canary Islands tax-Ds cannot be verified against the European system.