Hello @荞麦麸 ,
Welcome to the atlassian community!
You can use JIRA to manage it's own users, or you can connect JIRA to an external user management system.
https://confluence.atlassian.com/adminjiraserver070/user-management-749382766.html
Create, edit, or remove a user
https://confluence.atlassian.com/adminjiraserver070/create-edit-or-remove-a-user-794199053.html
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