You may be able to get the existing shaft fixed by cutting off the ends and welding on new shaft halves. If you don’t have the skills a drive line shop may be able to do it.
see this link for details
qualityfarmsupply.com
may be cheaper to just buy the whole thing if you can figure out what ends you need. I imagine there are a few different types to choose from.
PTO shaft assemblies from Agri Supply® can help you complete your PTO shaft with replacement parts or get a full new PTO shaft.
www.agrisupply.com
you may be able to find the correct information about the shaft in the implement’s owners manual