Hello, actually I am not able to "Tap to Click" at Login screen, but tap to click is working after login screen so there's no issue of trackpad and before it was working but after i created the new user acc

That is normal. Hard press the trackpad to register the click.

Tap to Click feature will be activated once the user login.

Best.

The Mac does not know it is you until AFTER you login, and can then read your trackpad preferences. Before that you could be anyone, including someone that has motor reflex difficulties that would make tap to click a problem.

dominic23: It is better to stay silent If you don't know the solution

Here is the solution for old track pads:

sudo defaults write -g com.apple.mouse.tapBehavior -int 1

and for multitouch trackpads:

sudo defaults write com.apple.driver.AppleBluetoothMultitouch.trackpad Clicking -int 1