Type it in notepad, then copy it in game
That's what I do too. I have a saved .txt file full of such IC scribblings. Everytime the server resets, the notes that Viorica and her cohorts leave for each other at their "spy house" vanish. So the file has the notes verbatim, with each line preceded by "@write title", "@write" or "@write add" as necessary. It makes replacing the lost notes a snap.
It's even easier for mass copies, like the flyers for Viorica's book peddling. Just put five or ten blank papers in the same "page" of the backpack. Copy the title ("@write title Hey, look! I'm selling the Frugal Trader again!"). Use the quill on one paper. Enter, Paste, Enter. Use the quill on the next paper. Enter, Paste, Enter. And so forth. Once all the papers have titles, move to the body. "@write Yep, Viorica has books. Come get some! Blah blah blah blah, yadda yadda, blah blah blah oops, running out of space, time for the next line. Don't forget to copy the two spaces on the end here. " Activate quill, Enter, Paste, Enter. Activate quill, Enter, Paste, Enter. Activate quill, Enter, Paste, Enter. And then copy the next line of the flyer. "@write add Yep, that's all I have to say. Come buy my books!" Activate quill, Enter, Paste, Enter. Activate quill, Enter, Paste, Enter. Activate quill, Enter, Paste, Enter....
If you've ever worked an administrative or clerical job (like I have), it's really not that hard.