Dear Aspirant,

Almost all of the examination conducting sites have a method to recover the password or application id(user id). All you have to do is just click on the forgot password button or forgot application id button. 

If you are not able to find the respective button on the login page then you must try to look for it somewhere else on the website. 

NOTE: As you have not mentioned your exam of interest I was unable to guide you further. Comment your examination type to get further assistance.

Thank You.