How to add a submit button?

Hello,

I have sent out Form to individual for them to complete. It is the same form I have shared with other Team Members previously and they have been able to complete in a Digital capacity with no problem. When I viewed the form after the individual told me that there was unfortunately "No Submit Button," I was able to confirm there is indeed not a submit button, so they are unable to complete the Form and get it back to me. Why would this be? Can you resolve 

I have just checked your form and I can see the submit button missing, it can be added on the form builder, click on the add form element section, drag the submit button and drop it to your form: