Monitor and Display | which is the right word that depict the visualization of the instruction in the computer ?

Monitor and Display both are different words with different meanings.

Monitor as per name its shows the observation of the work on a continuous basis or time period.
The display is known as an electronic device that uses a graphical presentation.

Monitor:

Yes, we are talking about the computer monitor that is an electronic device used for the presentation of instruction in a graphical view.
The monitor is known as an output device while the keyboard mouse is known as an input device.