GRUB

# If you change this file, run 'update-grub' afterwards to update                                                                      
# /boot/grub/grub.cfg.                                                                                                                 
# For full documentation of the options in this file, see:                                                                             
#   info -f grub -n 'Simple configuration'                                                                                             
                                                                                                                                       
GRUB_DEFAULT=saved                                                                                                                     
GRUB_SAVEDEFAULT=true                                                                                                                  
GRUB_TIMEOUT_STYLE=menu                                                                                                                
GRUB_TIMEOUT=2                                                                                                                         
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`                                                                       
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nvidia-drm.modeset=1"                                                                         
GRUB_CMDLINE_LINUX=""                                                                                                                  
                                                                                                                                       
# Uncomment to enable BadRAM filtering, modify to suit your needs                                                                      
# This works with Linux (no patch required) and with any kernel that obtains                                                           
# the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...)                                                               
#GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef"                                                                             
                                                                                                                                       
# Uncomment to disable graphical terminal (grub-pc only)                                                                               
#GRUB_TERMINAL=console                                                                                                                 
                                                                                                                                       
# The resolution used on graphical terminal                                                                                            
# note that you can use only modes which your graphic card supports via VBE                                                            
# you can see them in real GRUB with the command `vbeinfo'                                                                             
#GRUB_GFXMODE=640x480                                                                                                                  
                                                                                                                                       
# Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux                                                          
#GRUB_DISABLE_LINUX_UUID=true                                                                                                          
                                                                                                                                       
# Uncomment to disable generation of recovery mode menu entries                                                                        
#GRUB_DISABLE_RECOVERY="true"                                                                                                          
                                                                                                                                       
# Uncomment to get a beep at grub start                                                                                                
#GRUB_INIT_TUNE="480 440 1"     

On ubuntu 18.04 grub is in /etc/default/grub
sudo update-grub to update
dont forget to backup your existing grub