How do I fix incorrect password issue when logging into iTunes on PC?

Every time I log onto Apple it says the password is incorrect. I reset it and then I go round in circles. Been happning for ages and is driving me nuts.

I can log onto iPhone fine using biometrics and checked password I am using is OK but still no joy when I log onto iTunes on PC. Desperate to find out where all my uploaded music is.

[Re-Titled by Moderator]