can we mark * on the fields which are being made Mandatory by using "fields required" workflow validator?

[Nic Brough -Adaptavist-]

Validators in themselves do not affect the display - specifically, validators only run when the user attempts to commit the transition.  Which is far too late for them to affect the display of the screen.

Some add-ons can inject the markers required, but they don't do it via the validator really.