backup SQL server configuration

why do you  need SQL server configuration ?
if you need to setup a DR for SQL server , Backup restore the DB that you want and then enable log shipping.
https://www.mssqltips.com/sqlservertip/2301/step-by-step-sql-server-log-shipping/

should be of help

I mean SQL server configuration.

SQL Server configuration information are stored in master database but it will be a catastrophe if you copy everything. What kind of configuration information that you need?

I want to quickly setup another SQL server without copy and paste all existing setting .

I guess it will take more time as you might for sure stated by now.
What you can do is when setting up the next SQL Server instance, is to save the setup configuration file so it can be used for the next SQL Server installations.

"What you can do is when setting up the next SQL Server instance, is to save the setup configuration file so it can be used for the next SQL Server installations."

as long as I can remember this is what the only thing i can thing of, so other than this, nothing we can do AFTER SQL server setup  ?

You can still get the configuration file from the old installed SQL Server instances. Each SQL Server installation generates a configurationFile.ini file. Use that one from the source SQL Server instance that you want to get the configurations from.
Example from my local SQL Server installation: C:\Program Files\Microsoft SQL Server\140\Setup Bootstrap\Log\20170830_095722\ConfigurationFile.ini

tks. but that file can ONLY be used during MS SQL installation, but not after the installation, right?

yeah, the only way ! not AFTER that.

tks.