Install Apache httpd on CentOS Stream 9  

Install Apache httpd to configure Web Server.
[1] Install httpd.
[www@root ~]#
dnf -y install httpd
# rename or remove welcome page

[www@root ~]#
mv /etc/httpd/conf.d/welcome.conf /etc/httpd/conf.d/

[2] Configure httpd. Replace Server name to your own environment.
[www@root ~]#
vi /etc/httpd/conf/httpd.conf
# line 91 : change to admin's email address

# line 100 : change to your server's name

# line 149 : change (remove [Indexes])

Options FollowSymLinks
# line 156 : change

# line 169 : add file name that it can access only with directory's name

DirectoryIndex index.html
index.php index.cgi
# add follows to the end
# server's response header

ServerTokens Prod
[www@root ~]#
systemctl enable --now httpd

[3] If Firewalld is running, allow HTTP service. HTTP uses 80/TCP.
[www@root ~]#
firewall-cmd --add-service=http

[www@root ~]#
firewall-cmd --runtime-to-permanent

[4] Create a HTML test page and access to it from any client computer with web browser. It's OK if following page is shown.
[www@root ~]#
vi /var/www/html/index.html
<div style="width: 100%; font-size: 40px; font-weight: bold; text-align: center;">
Test Page