Code of customer, supplier on document now?

Yeah. I think default themes should show everything.

If you don’t want to see the customer or supplier code, you can edit the theme to remove the variable. Make sure to upgrade to the latest version (16.11.63) as editing themes has been more streamlined.

See: [16.11.24] Added ability to create custom themes

In your case, when you edit theme, look for {{ recipient.code }} which is a placeholder for customer code or supplier code. So just remove the placeholder from your theme.