Hello, Embassy of Canada sent below to me, when I asked them the process. Hope this helps.
I've added my comments in
Italics.
Embassy of Canada
Torre Espacio
Paseo de la Castellana, 259D
28046 Madrid
AUTHENTICATION OF SPANISH DOCUMENTS FOR USE IN CANADA
Authentication is not a common practice in Canada therefore the requirement to authenticate a document is determined by the authority to which the document is being submitted. Please contact the Canadian authority to whom the document will be submitted in order to confirm whether they require that the foreign document be authenticated for its use in Canada. Please note that only an original document bearing the signature of the competent authority may be authenticated. The norms established by the Spanish Ministry of Foreign Affairs for the authentication of official documents issued in Spain to be used abroad are the following:Birth/marriage/death certificates, certificate of “solteria”, criminal record check and notarial documents that have already been stamped by the Colegio de Notarios:
STEP 1 (You have to get the PCC obtained in Bcn authenticated with an original signature from the Ministry of Justice in Madrid. If I remember correctly no appointment is needed, but recheck)
Ministerio de Justicia
Plaza Jacinto Benavente, 3
28012 Madrid
University degrees:
STEP 1
Ministerio de Educación
Paseo del Prado, 28, Entreplanta
28014 Madrid
For other types of educational documents please consult the following link for further
instructions:
http://www.exteriores.gob.es/Portal/en/ServiciosAlCiudadano/SiEstasEnElExt
ranjero/Paginas/Legalizaciones.aspx
STEP 2 (Authenticate the document at the Ministry of Foreign Affairs.)
Ministerio de Asuntos Exteriores y de Cooperación (MAEC)
Sección de Legalizaciones
(Address as of September 1st, 2017)
Calle Pechuán, 1
28002 Madrid
By appointment: Please visit the website below in order to access the online “cita previa” system to make an appointment:
https://sede.maec.gob.es/pagina/index/directorio/cita_previa Ensure to print the “cita previa” confirmation receipt indicating your reference number and bring it to the appointment.
By registered mail:
Send the document(s) to be authenticated by registered mail along with a letter indicating your name and telephone number and a pre-paid pre-addressed “Postal Expres” envelope for the return shipping.
By hiring the services of a “gestor”:
You may hire the services of an official “gestor” in Spain for them to authenticate your
document(s) on your behalf.
Step2.1: Get the Authenticated document translated (list of sworn translators www.maec.es servicios al ciudadano, lista de traductores jurados)
Step2.2: Bring the document to Ministry of Foreign Affairs again to authenticate the translator's signature (I did not do this...)
STEP 3 (Authenticate the document at the Embassy of Canada in Madrid.)
The consular services of the country where the document will be submitted, in this case,
the consular services of the Embassy of Canada in Madrid:
Embassy of Canada
Torre Espacio
Paseo de la Castellana, 259D
28046 Madrid
No appointment required. walk in on Tuesday and Wednesday between 09:00-12 :30
The fee for an authentication is of 50 Canadian dollars payable by credit card. This fee
may be modified without notice.
The documents that are not written in English or in French have to be submitted with an
official translation to English or French.
P.S.: I have submitted my PR application to IRCC and yet to hear back from them