How can I send a sms or text message to a customer.

Thank you for reaching out to us.

To clarify, you want your customer to receive an SMS notification upon completing the form, right? If so, we do not have a direct way to do this using JotForm only. I'd recommend checking this Support ticket below, my colleague has provided a workaround, which I think is really helpful.

https://www.jotform.com/answers/1434385-How-do-I-send-SMS-text-messages

I hope this helps. Let us know if you need any further assistance.