Click on the Add Content tab (1) and you should be able to see the Form widget on the right (2).
Select the Form widget and drag it to your page (1)
When you Copy (1) a widget, the widget will be saved on the left of your site. Go to another page and drag the copied item (2) to your page.
Click on the widget to change the settings. The settings menu will appear on the left side of the editor.
1. Give a name to your contact form
2. Change the text that will appear in your submit button
3. Introduce the email where you want to receive completed forms
4. Take your users to a different page when they complete the form
5. Don't forget to save your changes when you finish