I have login screen that contains user id (text)and password(password). when the use will give input to login screen that user id and password must match with database for availability. if true it will go next screen otherwise it will be give a error message.
By the way i don't understand where exactly you are trying to implement this feature?
Is it after login into the pega application using the OOTB operator or any other way, can you explain your requirement in detail for better understanding as every Pega Portals have the OOTB login feature.