You probably need to do a lot more research if you are asking these kinds of questions, my friend! But anyway, here are some clues. Now ICOs require people to "whitelist", meaning they register their addresses and emails, and then only after approval are they allowed to invest (this is not a donation, by the way, although literally the way ICOs run yes you are actually donating money!). Then, every account is linked only to an address already whitelisted.
Thanks to blockchain, it is easy to check how much each address sent to the ICO.
That's good then