I use a folding bone for test-folding printed sheets in the printshop where i work. They are pretty hard to come by these days so i designed one myself.

When i get my hands on some nylon i will print one with it. PLA just isn't tough enough to withstand many folds.

I uploaded the .skp file so you can customize your own in Sketchup.
Just place text on the surface (on intersect plane) then explode the text component and push/pull the text to the desired depth (i used 2 mm's).