How can I create a form to make multiple submissions without reopening the form?

I'm sorry, but I don't fully understand your question.
Can you clarify it a bit more?

Basically, you need to open the form to make a submission so I'm not sure what is exactly what you're trying to accomplish. If you can provide more details so we can better understand the situation it would be a great help for us to give you proper assistance.

We'll wait for your response.