FAPatch[] is an auxiliary function that patches FeynArts to be compatible with FeynCalc. If an unpatched copy of FeynArts is present in $FeynArtsDirectory, evaluating FAPatch[] will start the patching process.
Overview, PatchModelsOnly, FAModelsDirectory.
Setting the option Quiet to True will suppress the ChoiceDialog asking whether you really want to patch FeynArts.
(*FAPatch[Quiet->True]*)If you just want to patch some new models (e.g. generated with FeynRules), while your FeynArts version is already patched, use the option PatchModelsOnly.
(*FAPatch[PatchModelsOnly->True]*)The model files do not necessarily have to be located inside FileNameJoin[{$FeynArtsDirectory, "Models"}]. A custom location can be specified via the option FAModelsDirectory as in
(*FAPatch[PatchModelsOnly->True,FAModelsDirectory->
FileNameJoin[{ParentDirectory@NotebookDirectory[],"FeynArts","MyModel"}]]*)