Syncing/Copying Data from Different Modules

Syncing/Copying Data from Different Modules

Hi,
I am trying to automatically copy data from one field in one module(Deals) to copy that same text to another field in another module(Companies)

i.e. 
At the end of the deal process, user needs to add the account number as a final action.
Once added, is it possible, with using workflows, to update and copy that same acc number into the companies module?

Thanks