The Community Administrator can be a neighbor (“any” neighbor) or a qualified person. LPH states that has to be a person with a professional qualification legally recognized to work as such.
Before the UE regulation, it was clear that the law meant special qualification and being a member of a professional association (Colegio de Administradores de FIncas, or similar).
But, after the EU free competition regulation (deployed in Spain in two laws, commonly named Ley Onmibús and Ley Paraguas), the access to the market has to be as free as possible. This means, that nowadays almost anybody can be “administrador de una comunidad”.
It is up to the consumer – the community – to choose among all the possibilities.
My advice? Always choose someone that belong to the professional association “Administrador de Fincas”. This way, you are not only sure about the professional knowledge, but also that the professional has an insurance policy, and you can ask for advice (or complain) if the professional hired doesn’t do things the way you think he/she should do them.