Hello @GeorgeP512. It's great to hear that you are using our event tool to manage your event and registrations! I'd be happy to answer the questions that you have. Here is a link to an article from our Help Center that will show you how to include guests for an event. In regards to editing the language of the registration form, at this time, we are unable to change the language of the field. I apologize for any inconvenience this may cause you.
It looks like you have already made your event live but you can still have your colleagues test the registration form before you send it out to your contacts by using the Short URL for your event. I see that you have registration for your event closed so you will want to make sure to reopen the registration before sending out the link or the invitation for the event.