Can I create an email able receipt for cash donations?

We need to be able to send receipt for any cash donations we get for the rescue. Is there a sample online or a way to create a receipt with out processing the payment thru a form 

When your users submit the form and donate any amount they will receive an email (Autoresponder), but that will require that the payment is processed through the form.

I'm not sure how would you like to do this without processing the payment?

If you could shed some light on that, please?

Thank you!

We have donor who send us a check or stop by an adoption event and give us
cash. We are a dog rescue. We would like to email them a receipt for their
donation.
...

You can create a form that will only contain the email field, and submit button, so the receipt that you have created in the autoresponder will be sent to the person: https://www.jotform.com/help/26-Creating-a-Form-Autoresponder