You will need some development for it.  This question was posted in this forum:
https://sagecity.na.sage.com/support_communities/sage_erp_x3/f/sage-x3-general-discussion-forum/91695/how-to-do-inter-site-invoice/262004#262004

Thank you for the suggestion. I had already discovered that accounting had created a receipt  for a different site and was trying to invoice in a separate site. I am surprised that the system allowed them to pick the receipt to invoice.