First we need to use this command:
sudo dpkg-reconfigure xserver-xorg
Then, we need to edit this file to create the configuration
sudo gedit /etc/X11/xorg.conf
when you open the text file section replacement monitor to the bottom of everything with this text
Section "Monitor"
Identifier "Generic Monitor"
Option "DPMS"
HorizSync 30-71
VertRefresh 50-65
EndSection
Section "Screen"
Identifier "Screen0"
Device "Configured Video Device"
Monitor "generic Monitor"
DefaultDepth 24
SubSection "Display"
Viewport 0 0
Depth 24
Modes "1024x768" #Here you can use other size
EndSubSection
EndSection
