Getting married in Gran Canaria as a non-Spanish couple is such a faff that we advise you not to do it unless it is absolutely necessary.
If love is in the air and you absolutely have to tie the knot, then allow at least a year (really) to get all your paperwork shipped out from home, translated, checked, stamped, lost, and approved.
If one of you is Spanish, then it’s easier.
In Spain, the marriage certificate is called a Libro de Familia. You inscribe your children in the same booklet.
If the spouses (or spouses-to-be) are from different countries, once the marriage or birth takes place, be sure to take the certificate to the expat’s consulate, so the marriage/birth can be registered with that country. If you don’t, you may regret it eventually.
When marrying a Spaniard in Spain, you can choose between a religious ceremony or a civil ceremony. Before the wedding, you have to show proof of identity, and proof that you are not currently married. If you’re a Christian-but-not-Catholic foreigner getting married in a Catholic church in Spain, you may find the paperwork is easier than it is for your Catholic partner: You won’t need to show a Baptism certificate. The process of getting married starts with edictos (initial announcements of the wedding). If no one presents proof to the contrary, the ceremony can take place about 20 days later.
Getting married in the Catholic church involves some solemn (or comic, depending on your PoV) interviews with a priest. Just pretend to be virgins as it’s less awkward.
After the ceremony, you have to register in the Registro Civil, where the Spanish government will give you a Libro de Familia. This is the universal proof of your matrimony and of the children that you have, as well as other family conditions. Don’t forget to report your wedding at your own country’s Embassy or Consulate.
If you are married outside of Spain and one of the spouses is a Spanish citizen or legal resident (that is, with an NIE), the non-Spanish spouse does not automatically receive Spanish nationality. This person can get a reagrupación familiar visa before going to Spain. Once they are in Spain, the application process for the NIE will be easier. It will also take less time if they want to become a Spanish citizen. After the wedding, the Spanish citizen has to report the matrimony to the Spanish Embassy or Consulate, so it can be registered and validated in Spain. The Spanish Embassy or Consulate then gives you the Libro de Familia.