If I wanted to turn off screen time do I need a different password

The screen time passcode may or may not be different that the regular passcode that you use to unlock your phone.

It all depends on how you set things up. When you set up screen time, you were asked to select a password to enable that feature.

Did you select the same password or passcode that you normally use with your iPhone, or did you set up a different password or passcode to be used only with screen time?

Different from what?

The screen time passcode and the Lock Screen passcode are not linked to one another. I you set them both to the same thing, then they are the same... if not, then they are not.