The letter P on a blue and white sign indicates parking. In a blue zone, you'll have to find the ticket machine and display a ticket in your car. Yellow lines or a blue sign with a red border indicate no parking. Some cities have green or blue zones for different kinds of parking including residents only – the sign will tell you which.
As well as roadside ticket machines there are municipal and private undercover and open lot parking areas where you'll have to pay by machine or to the attendant.
Despite being in the EU, Spain and therefore the Canary Islands are not part of the Blue Disc scheme.
Enforcement of parking is often done the police although some towns and cities have parking officers. If parked illegally or causing and obstruction you will be fined and may have you vehicle towed away.
Disabled drivers are entitled to use allocated parking spaces under the Blue Badge scheme but should print off and display a notice in Spanish alongside their badge. The notice is available at http://www.fiadisabledtravellers.com/