A login is a security principal, or an entity that can be authenticated by a secure system. Users need a login to connect to SQL Server.
Security Manager provides an easy way to add, alter or remove users visually without typing an SQL code. To open the Security Manager, on the Database menu, select Security Manager.
To edit a user login, open Security Manager, expand the Logins node, and then select a required user login in the tree. After editing, click the Save button on the Security Manager toolbar to apply your changes. If you want to discard the changes, click the Undo button.
To delete a user login, open Security Manager, expand the Logins node, and then click Delete from the shortcut menu of a required user login; or select a required user login in the tree and click Delete.