My Apple ID password

If you forgot your Apple ID password - Apple Support

You can reset it using your email or mobile number as registered/associated with your apple account. By simply clicking forgot password from the login page. Or if you are already logged in then you can get this accomplished from account settings page

Your question seems to be a very random question without much details included, i would recommend you, to be more specific while seeking help from support community. like if there is any challenge you are facing in resetting your account password or have you lost access to your device/email etc.

see If you forgot your Apple ID password - Apple Support

from your IOS device.

settings> [your Apple ID]> Password & Security> change password.