@Анастасия Лосева Thank you for reaching out to us.
As I understand you want to know the process on how to register/create users using Microsoft Graph API.
You can follow the steps mentioned in this https://learn.microsoft.com/en-us/graph/api/user-post-users?view=graph-rest-1.0&tabs=http#:~:text=Example%201%3A%20Create%20a%20user which would help in creating a user using Microsoft API.
I have tested the same in my lab, it works as expected, reference below screenshot
Let me know if you have any further questions.
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