The following applies to version 7 and higher

To have your system start up in text mode

systemctl set-default multi-user.target

To have your system start up as a graphical target

systemctl set-default graphical.target

Start in Single User

systemctl set-default rescue.target

To check to see how it will start on next boot

systemctl get-default

To change the current runlevel without rebooting

systemctl isolate multi-user.target

If you have problems booting your system into the default (i.e. it is set to graphical.target and there is something wrong with the display card)-

• Based on your environment append systemd.unit=rescue.target, at the end of line starting with linux or linux16, for example below is a snippet from CentOS/Red Hat 8 node

https://www.golinuxcloud.com/boot-in-single-user-mode-rhel-centos-8-linux/