Am I able to attach a JotForm to an invoice sent through the invoicing system, Square?

Thank you for contacting us. I also recommend creating an account.

You can signup using your email account here https://www.jotform.com/signup

As to your inquiry, Square payment integration is available to JotForm.

Check the user guide: How to Integrate Form with Square

Let us know if you need further assistance.

Related guide: https://www.jotform.com/help/323-Mastering-Payment-Form-Integrations-with-JotForm