You can go to Active Admin Directory and add members to dbmanager and loginmanager roles. Otherwise, you can opt to use the Azure User Management console which is an open source that helps in managing the users and logins.
For more details, please refer to this blog. To download the open source, click here.
Here is a step to create a user and give them access to your database:
CREATE USER [user1] FOR LOGIN [computer_name\user1];
For more permissions, please refer to this blog.