KYC has to be performed by project owners, not by investors.
Know your customer, which is more commonly referred to as KYC, is the process of providing and confirming the identity of someone. In the context of a presale, it is often providing identification and addresses of the people that run the project.
The intention of KYC for projects is deter exit scams as their information could be passed on to the appropriate authorities or in some cases released to the public.
If a project has an approved KYC report from a reputable provider, a badge will be placed on the presale with a link through to the mentioned report. You can see an example below: