Personally I wouldn't see a problem with adding a notepad assuming it wouldn't be difficult or time-consuming enough to excessively pull away from other updates. As others have mentioned, most computers have a notepad built in so it might not be too useful for them, but would certainly be a haven for mobile users!
Just open you computer's notepad. If a notepad were introduced to osrs, I'd support it only if it were an item, not a menu iconBring back Stealing Creation! (with reworked non-OP rewards)
Support my forum post: Stealing Creation/New Rewards