Add Users to Jenkins with "Allow users to sign up" Disabled

I do not want new users to be able to sign up. So in Jenkin's Configuration, I disabled "Allow users to sign up" with using Jenkin's own user database.

But how can I manually add users now? Also, is there a default admin user I should take care of?

How do I enable Jenkins signup?

You have to first enable Security under "Global Security", and you have to select "Jenkins own user database" and do not forget to select all users have own rights and users can sign up themselves, otherwise you have blocked yourself quite efficiently.

There is "Create Users" in "Manage Jenkins".

In case "Allow users to sign up" was already disabled and security turned on and there is no user you can use to login the only way to go is to change Jenkins configuration manually on the server and restart server.

Thing to change is in Jenkins Home folder i config.xml file. change