sudo cvt 1920 1080 60

Declare New Resolution

Part of the output should be similar to this:

"Modeline "1920x1080_60.00" 173.00 1920 2048 2248 2576 1080 1083 1088 1120 -hsync +vsync" (w/o the quotes)
sudo xrandr --newmode "1920x1080_60.00" 173.00 1920 2048 2248 2576 1080 1083 1088 1120 -hsync +vsync

Determine Name of Display

sudo xrandr -q

Add New Resolution Mode to Display Device

sudo xrandr --addmode Virtual1 1920x1080_60.00

I tried this but can't find this resolution in SYSTEM SETTING - DISPLAY. Please help me to how add a custom resolution in my system. Thanks

You've missed out a step - so enter your above commands as well as (note that you don't need to use sudo for the cvt command):

xrandr --output Virtual1 --mode 1920x1080_60.00

You will now have a resolution applied, but it won't be selectable from the Display window and is only temporary. To make the resolution visible in the Display window, follow this answer.

If you choose not to do that, then you make the resolution permanent but not visible in Display:

• Create a bash script, xrandr.sh for example, and place your xrandr commands into it:

#!/bin/bash
sudo xrandr --newmode "1920x1080_60.00" 173.00 1920 2048 2248 2576 1080 1083 1088 1120 -hsync +vsync
xrandr --output Virtual1 --mode 1920x1080_60.00
• Make the script executable with chmod +x xrandr.sh