root@ubuntu-20-1:~# systemctl stop ufw

root@ubuntu-20-1:~# systemctl disable ufw
Synchronizing state of ufw.service with SysV service script with /lib/systemd/systemd-sysv-install.
Executing: /lib/systemd/systemd-sysv-install disable ufw
Removed /etc/systemd/system/multi-user.target.wants/ufw.service.

root@ubuntu-20-1:~# systemctl mask ufw
Created symlink /etc/systemd/system/ufw.service → /dev/null.