In mathematics, "permutation" is a technical term for ... excuse me if I don't have a technically correct definition here, but the concept is: the set of possible subsets of a given size in which order is important, or to put it another way, a mapping from an aribtrary set to a set of ordinals. But in common English, "permutation" simply means "variations" or "alternatives". Like, people will say things like, "What permuations of size and color will we produce of this piece of furniture?"
Note that it's not at all unusual for words to have a technical meaning in a specific context that is different from their general meaning. When a physicist talks about "work" and "energy" he means something far more specific than the ordinary uses of those words, etc.
As to your specific example, I don't know of a single word for that concept. Generally someone would refer to them as "alternative formats" or similar phrasing, as in, "Our computer system supports several formats for phone numbers."