Thanks for concern. As per above comment retrieved dnf.conf file from installation media.
It would be great help if you let me know the other ways around possible for the same in brief. Thanks again.
[chandu@centos-8 ~]$ sudo yum install --downloadonly --downloaddir=/home/chandu/dir1 httpd
Config error: Parsing file "/etc/dnf/dnf.conf" failed: Parsing file '/etc/dnf/dnf.conf' failed: IniParser: Missing '=' at line 7
I am getting this error while trying to download only apache web server...