You would typically use this along with the systems firewall to allow a port through. Guide for firewalld and iptables. If you change it in the firewall and fail to add/edit it in semanage you can potentially get weird behavior like sshd not wanting to start after changing the port.
semanage port -a -t ssh_port_t -p tcp 2222
The above command allows the sshd service to start, using port 2222.
So the command to allow port 80 through the firewall would be
firewall-cmd --zone=public --add-port=http/tcp
firewall-cmd --zone=public --add-port=80/tcp
The above command only works for the running instance of firewalld. If you want to add the port permanetely you need to run the above command and then run it again with “–permanent” added to the end of the command.