Is it possible to post a form for viewing access and then activate the submit button at a date/time?

I have vendor applications with requirements for supporting documentation.  I would like to post the application so that potential vendors can review the application and gather the required documents and then schedule the application to open up for submissions on a certain date and time.

What you can do is to hide the submit button through conditions ans show it at a specific date/time. Please follow this guide: https://www.jotform.com/help/439-Conditionally-Enable-or-Disable-a-Form-Based-on-Time

Instead of hiding all fields, just hide the submit button. Let us know if you need more help.