This is a binary ionic compound (an ionic compound consisting of two elements). The stock method of naming ionic compounds can be applied here.
First, identify and name the cation (the positive ion): Here, that would be the calcium (Ca2+) ion.
Next, identify and name the anion (the negative ion). Here, that would be the fluoride ion (F-). The anionic form of an element’s name can often be obtained by retaining the root and replacing the ending with -ide (e.g., sulfur becomes sulfide; oxygen becomes oxide; nitrogen becomes nitride; chlorine becomes chloride; bromine becomes bromide; etc.).
So the systematic name of CaF2 would be calcium fluoride.