Until now, you had to create separate forms one for each language. Now, with the addition of Contact Form 7 Multilingual, you can create one form and use it for all your site’s languages. You will insert the same form into pages in different languages and WPML will allow you to translate the texts that appear in the form.
The Contact Form 7 Multilingual plugin lets you translate forms, without having to create separate forms for each language. Go to WPML->Translation Dashboard and select Content Form.