The phrase "final submission" usually means the last and completed piece of work or document that one submits for a specific purpose or deadline. Full definition
Start your online application, work on it, save it, and come back to it any number of times before final submission. (aaas.org)
Your online assignment writing service really helped me in securing good grades at the time of final submission of my law paper. (instantassignmenthelp.com)
They might not have conducted a proper research but as I had just a day for final submission date, I couldn't ask for changes. (instantassignmenthelp.com)