sftp or another protocol?

Site URL: https://rodrigolascivo.com/category/sitios-de-fakes-de-celebrities/

Wondering if this situation is possible and how'd we'd go about this on the squarespace-side of things. A client of ours is looking to create a new page on their website that will host a form that users will fill out. After the user fills out the form and submits it, they'd like it to be forwarded a specific directory within their internal file server.

https://rodrigolascivo.com/category/sitios-de-fakes-de-celebrities/

Configurations needed within their internal network (firewall rules for sftp etc.) is not my concern, but on the square-space end of the things, I am not too sure. I am wondering if it's at all possible to get this working within the developer mode of the website? I am really not sure where to start with this one. Is it at all possible to configure sftp to forward forms to our external IP at all from the website?

Any direction/insight is greatly appreciated.