1. Is the "value" referred here is the total number of new lines or white spaces which follow that variable

The "value" is the total number of strings removed which are defined by the $/ variable.

2. If so in which location does it stores this value.

It does not store a value but it does return a value which can be assigned to a variable.

3. Can we access this "value" by using any command.

You can assign it to a variable using the assignment operator.