My wife and I got married in PP a couple of years ago. Lots of paperwork but totally worth it. We have a Libro de Familia which I heard they were scrapping but not sure sure, and it's registered in Pollensa.
For it to be a legal wedding you either need to be having a Catholic ceremony with permission from your local parish or be marrying a Spanish national. Otherwise it's just a ceremonial type thing and the real thing back in UK.
There's loads of great info on various Facebook pages, which I have to confess my wife dealt 95% of the time and I just went along with it.
If you do decide I can highly recommend Alcanada Golf for the celebration, they do brilliant packages, food was incredible and the service was also outstanding.