You can reset your password in 2 places. This is available to accounts that were created with an email. Accounts created with Sign in with Apple or Sign in with Facebook do not have passwords.

If you are not logged in you can reset your password from the Login page. Tap the Forgot your Password? option and enter your email address. Make sure you enter it in lower case letters.

If you are logged in you can reset your password from the Account page. Tap the Change Password option and verify your email address. Since you are logged in the email is populated for you.