Hello Sandhya,  if you have forgotten the user ID try to retrieve it by finding the user ID in your registered mail ID, they might have given your credentials at the time of your registration so try checking the mail and also check spam mails too. Once you are able to retrieve the user ID you can go to login page and click on forgot password then follow the instructions they ask you to do by this way you can be able to retrieve your ID and password.

If you find any difficulties, feel free to ask.

Thank you.