Hello andyallen,
Thanks for visiting the Community. Allow me to jump in and add some details to the response given by @Anonymous.
As mentioned by @Anonymous, you can enter as many characters, as long as they fit in the box. I did it in my sample company file and I was able to enter 250 characters including spaces.
This should help you in estimating the length of the message for your employees.
The Community is a great avenue to connect and interact with accountants and other users. Let me know if you have other questions in QuickBooks Desktop. I'll be around!
