Press e when the menu shows up and add them on the linux line:

linux /boot/vmlinuz-linux root=UUID=978e3e81-8048-4ae1-8a06-aa727458e8ff quiet splash

Press b to boot with these parameters.

To make the change persistent after reboot, while you could manually edit /boot/grub/grub.cfg with the exact line from above, the best practice is to:

Edit /etc/default/grub and append your kernel options to the GRUB_CMDLINE_LINUX_DEFAULT line:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

And then automatically re-generate the grub.cfg file with:

# grub-mkconfig -o /boot/grub/grub.cfg