When you hit the 'printer' icon it should bring up a box "Print This Client"

there are 3 rows of options to print  "Filing Copy", "Client Copy", and "Preparer Copy"

To the immediate right of those words, there is a box marked "Watermark",  just uncheck that box,

I leave those boxes unchecked on the filing copy, which is very rarely a need, and on my preparer copy...just cause I'm a nerd and i want my file copy neat, but always leave it checked on the client copy.

Also, you can put any words you want as the 'watermark', like DO NOT FILE, or CLIENT COPY, or WHO'S YOUR DADDY?, etc.