Step-1)For Login and SignUp I have the entered email, Password to signup or login and then Logging out.
Step-2)Again when i click the signup button to either login or signup still the previously entered user fields are visible.
May I know how to clear the fields after the user gets logout?So that when I Login again I should not see the previously entered login details.
You should be able to run the Reset data action as shown below.
Just target the popup or the group for which the fields are in, although depending on how you have the values set it may not work. Try it anyway!