Adding additional fields to item details

Hi,

I am looking a way to add additional custom fields to uploaded item details. Right now I am able to add a comment however looking at adding additional fields within the tab. If anyone can point me in the right direction, I would be very grateful.

Thanks

Can you use the tagging system maybe? Can you ellaborate what exactly you are trying to do?

I am looking to add another tab after Version that say Buy

and has a fillable table like my mockup attached. The table will expand as needed.