If you know you don’t know your password, you need to recover your account. Just below the login password entry field on Facebook’s sign-in page is a link: Forgot account?
Facebook Forgot account? link
Click that, and you’ll be taken to a page where you can enter the email address or phone number associated with your account.
Facebook Find your account
You’ll then be presented with a list of account recovery options associated with your account.
Facebook reset your password
Select the one you want to use and click Continue.
I hope these steps will be helpful!
Mark Wilson