First of all, you enable that your Administrator (standard profile: MxAdmin) can navigate to your ‘Accounts’ page of your Administration module.
Secondly, you enable your Production security:
You then run/deploy your application, log in with your MxAdmin and correct password, create an account as you wish and log in with it.
Hope this helps.
Thank you, I actually meant how to login through the Mendix application like the web browser and not to the Mendix platform
The account must be present in the database to be able to login.
You can create/adjust the admin account here, which you can use to create other users: