When someone opens a template for the first time, they should not have to guess what goes in each field or stop to ask a colleague. Notes and hints give them the context they need, right where they need it.
Fewer mistakes, less back-and-forth
Notes before a document is created are the first thing a person sees when they open the template: what it is for, what to have ready, which fields need care, who has to approve what.
Every field carries its own hint, such as The customer's legal name or Gross annual salary in USD, shown while it is empty and as its label in the form, so nobody needs a separate instruction sheet.
Notes after a document is created go with the finished document: who it is sent to, where it is filed, what happens next. They can name the document itself, Invoice 0013 for Blue Harbor Ltd. is ready: email it to the client, and they stay on the document's record.