I do not have the function DATE.DIF

Good morning,

I have a weird problem with excel. In the laptop that I am using, I have never had the function DATE.DIF. I wonder why I don't have this function on excel. Nevertheless, I need it and I have already contacted technical support of Microsoft but he did not manage to sort my problem out, and he advised me to write in this community.

Excel version 2104 build 13929.20386

Windows 10 home, version 20H2

Please note that my language in my computer is Italian.

I thank in advance anyone will help me