CIAM exists is part of a workflow for your customers or users, with the end goal of getting access to your applications functionality or data.
When you register for an application in CIAM, users usually provide their own credentials. Depending on the application is, there are additional forms of identity proofing that may be required.
Identity proofing is the process of proving who a user is and connecting that identity to an online account, typically the one just registered.
For a business application that a user is trialing, they might need to prove they own the email address you provided by verifying it.
For a money transfer application, they might need to prove they have a real bank account by providing two numbers of pennies that were deposited into their account.
For an application with legal ramifications such as signing into a government program, the user might need to provide government documentation and proof that it is theirs.