The most important thing about a mufti is the thing most often lost in reporting: a fatwa is an opinion, not a verdict, and it binds nobody.
The nature of a fatwa
A mufti issues fatwas, reasoned legal opinions in answer to questions put to him. A fatwa has no enforcement behind it, the questioner may seek another and act on it, and two qualified muftis may answer the same question differently without either being in error. What a fatwa carries is the authority of the reasoning and the reputation of the man giving it, and nothing more. A mufti must be trained in the sources and in a school of law, and there is no ordination; the qualification is scholarly and recognised by other scholars.
The contrast with the judge
The clean contrast is with the qadi. The qadi decides a case between parties and his judgment is enforced; the mufti answers a question and his answer is not. Many states now appoint an official Grand Mufti, which places state authority behind particular opinions and makes the office political in a way the classical role was not, but the underlying character of the fatwa as advice rather than command is what the modern use of the word, and the alarm it often causes, tends to obscure.