Spain will have its own Covid certificate or passport in June, although pilot tests will begin with it this May. At the moment, it is a certificate sponsored by the EU that will be used only to facilitate travel within the Union itself, but it is not intended to serve other purposes, such as entry to mass events or in closed spaces.

Work is in progress to facilitate the “Passport” which will be called a “Digital Green Certificate” more details can be found on the following EU link

https://ec.europa.eu/info/live-work-travel-eu/coronavirus-response/safe-covid-19-vaccines-europeans/covid-19-digital-green-certificates_en