Add a date and time hidden field in a form

I want to add a date / time stamp in a hidden field on a form so I know when someone submitted the request, I am sure this is a simple thing to do. I know how to insert a hidden field, but not how to insert a date and time. I am using a vb time stamp to print a time on the screen, but can I use the literal ID to save as data into the record? or do I need to add a hidden field, and how would I insert the current dat/time into that field?

 
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