First, download the rpm package:
$ sudo rpm -Uvh https://repo.zabbix.com/zabbix/4.2/rhel/7/x86_64/zabbix-release-4.2-1.el7.noarch.rpm
Next, install it using yum:
$ sudo yum -y install zabbix-agent
Make sure to edit /etc/zabbix/zabbix-agent.conf with the proper zabbix server info/config.
Finally, to start the zabbix service:
$ sudo service . . . → Read More: Install Zabbix Agent on CentOS7