how to create virtual drive in windows

The drive letter you assign represents a virtual drive, because you can use the drive letter in commands as if it were a physical drive

Syntax
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SUBST /?

SUBST [drive1: [drive2:]path]

SUBST drive1: /D

Display names of the virtual drives in effect:

SUBST

example:
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This command creates a virtual drive Z for the path d:\halim:

SUBST Z: d:\halim

Now, instead of typing the full path, you can reach this directory by typing the letter of the virtual drive, followed by a colon, as in:

z:

This example works only if you have included the line LASTDRIVE=Z in your CONFIG.SYS file to define Z as the highest letter that the operating system recognizes as a disk drive. For more information, see the LASTDRIVE command.