Users need to be identified initially to get their account data. Using a well defined process they are handed their account data, their credentials or even better also a second factor like a smarcard, an OTP token or some other personal belonging like a smartphone.
These processes need to be well defined and running smoothly especially if there are huge numbers of users involved.
E.g. at a university every year several thousand new students come and go, get new accounts and leave the system. Students re-enroll or graduate and leave the university. Those well defined processes help to ease the job of the IT and also help to save money.
NetKnights helps you with planing, defining and implementing those processes. As an example when enrolling two factor authentication to the users, you can use privacyIDEA. Its simple REST API, the ability to utilize the special registration token and the PIN letter functionalities guarentee a smooth and secure enrollment.