Fluorinated molecules have a wide range of applications and are used as medicines, agrochemicals and refrigerants and in smartphone liquid crystal displays, photovoltaic solar cells, Teflon tapes and the coatings of textiles and buildings. Fluorination and fluoroalkylation — incorporation of a trifluoromethyl, difluoromethyl or monofluoromethyl group — are the major strategies used for the construction of carbon–fluorine bonds and fluorinated carbon–carbon bonds, respectively. The past two decades have witnessed a rapid growth in fluorination and fluoroalkylation methods thanks to the development of new reagents and catalysts. This Primer aims to provide an overview of state-of-the-art strategies in fluorination, trifluoromethylation, difluoromethylation and monofluoromethylation, with an emphasis on using C–H functionalization, although other strategies for fluorination and fluoroalkylation are also discussed. Further landmark achievements are expected in the fields of fluorination and fluoroalkylation as organofluorine compounds are used increasingly in everyday applications. This Primer describes contemporary fluorination and fluoroalkylation reactions in chemical synthesis. The authors describe the main fluorination and fluoroalkylation reactions. The many applications of these reactions in pharmaceuticals, imaging agents and agriculture are discussed, along with the history and future of synthetic organofluorine chemistry.