The ideal window for socializing (or acclimating cats to people) is when cats are young kittens. It is very difficult, and often impossible, to socialize an adult feral cat who has lived outdoors her whole life. Alley Cat Allies does not recommend attempting to socialize adult feral cats and promotes devoting time, energy, and resources to Trap-Neuter-Return (TNR) instead. TNR programs are the best way to help the most community cats.
Learn more at https://www.alleycat.org/resources/why-its-trap-neuter-return-not-trap-neuter-adopt/.