Currently you can write on a piece of paper and then stick it to a airlock as a semi permanent note or warning. However you can’t do this for walls, windows, windoors and shutters. This is inconvenient as there isn’t always a airlock in the spot where information is needed to be relayed.
My suggestion would be to make custom posters with Paper + Tape that can be placed on walls just like wanted posters and other Posters.
This would be good for the game as cooks and bartenders could make custom menus. Similarly Geneticists could advertise what genes they have available to dispense. As it would use the current Markdown system it could also be used to make sign up sheets for things and the HoP could use it to make instructions on his window for common requests and questions and all departments can use it to make out to lunch notices etc.