I'm not an official at Cosmo or Epayments, I'm just sharing some of my accumulated knowledge here.
KYC is basically the Know Your Customer standard. Mainstream sellers and freelancers undergo it too by the way.
The components are usually a proof of residence in the form of a utility bill or a rental contract (in some cases both),while in some EU countries a bank statement can suffice too. The 2nd component is a form of an ID which will be a passport, driver's license, or a national ID. Per what I know, a voter's card, student cards, and a military ID, will usually not suffice (years of assisting Nigerian technical writers will expose you to lots of cool stuff, that is esoteric and useful at the same time
)
There are some countries in which a proof of residence can entail a little extra work, because there's no written rental contract, or the bills are under a spouse or a landlord's name. These will usually be reviewed on a case by case scenario. A seasoned support rep with an understanding of how certain countries list residence and ID's (don't get me started on Thailand and Cambodia, it can be harder than a Google interview
), can usually help through this with efficiency.
I just wish providers would use less unique internal lingo, and simplify the instructions to earth dwellers language sometimes
I hope it helps, and if it saved some time and effort to at least one user, I'm happy.