Anonymisation strips the identifying details out of data. Names, emails, and ID numbers come out (or get masked), leaving the useful shape behind, the trends, counts, and patterns, without the people. Done well, no one can be traced from what remains.
It is the safe move before sharing data with an AI tool when you only need the analysis, not the individuals. Note the weaker cousin: pseudonymisation swaps identifiers for codes but can be reversed, so it is not the same as true anonymisation.