The synthesis of Alkyl Fluorides is best accomplished by

The best way to prepare alkyl fluoride is a swarts reaction in which inorganic fluorides like silver fluoride or antimony trifluorides are used with a corresponding alkyl halide. For example, the preparation of methyl fluoride.

CH_3​Cl+AgF→CH₃​F+AgCl

One of the more advantages of the reaction is that AgCl is solid so it precipitates out and we will get pure alkyl halide.