Hello! I remember! @lubos mentioning here in forum another login way for manager.io in case if we want to hide identity of manager. Unfortunately, i forgot and also searched the forum but can’t find it.
If any user can help, I’ll be thankful.
Are you thinking of something in the server installation instructions available here: Installation | Manager?
You can log in with subdomain.manager.io or subdomain.accounting.link
Dear @Abeiku, thank you such much. This is exactly what my question was about. I have got my answer.
Just one more question, is there a way to change subdomain name.
@Tut, thanks for your response. May be, my question was not too clear
Go to cloud.manager.io and click on the “Change Domain Name” button.
@Abeiku
I have changed the subdomain name as per method advised by you and it was successfully done. But, i noticed that the old subdomain name can still be used to login to manager 
The purpose to change subdomain name was to restrict login with old name.
I’m nonplussed as the purpose to change subdomain name seems fruitless.
So, usually, once the subdomain is renamed or name charged, it should become obsolete and couldn’t be used to login any more. The subsequent login should have only be done by new name.
@lubos, is it a bug? Or just a normal expected behaviour?
A domain name resolves to an IP address.
There is no restriction on how many domain names can resolve to the same IP address. If you what complete control of your domain name, you can register what ever domain name you want with a domain name hosting company, then point it to the same IP address.
Lubos posted earlier that the subdomain.accounting.link is designed to be an additional link / domain name. I assume to ensure uniform support of all of the other feature offered by the NG Software cloud product. See About server edition - #2 by lubos and Custom domain - #2 by lubos threads