I didn’t want to generate panic 
The installation already sets up most of the things for hibernation (if you choose swap with hibernate). The only missing part is the dracut part.
It’s easy to fix that:
first generate the dracut configuration file for hibernation:
cat <<-EOF | sudo tee /etc/dracut.conf.d/resume.conf
add_dracutmodules+=" resume "
EOF
and regenerate initramfs
sudo dracut-rebuild
And reboot.
IMPORTANT: the above instructions assume that the other configuration parts for hibernation are already in place: SWAP partition in /etc/fstab and the correct resume option in /etc/default/grub.
As I said, the above two steps are implemented by the installation if you selected swap partition with hibernate.
Otherwise, if you did not select that option, you’ll have to perform a few additional steps. I summarized them here: https://www.lorenzobettini.it/2022/12/enabling-hibernation-in-endeavouros/
Hope it helps.