Stickers are often used as reminders that can be placed next to things to help remind people to do something. They might be placed next to rubbish bins, recycling containers, light switches, taps and computers, to prompt people to do something to help the environment.
If using stickers, find out if it is OK to do so. Make sure that paintwork is not damaged when using stickers. Often a product like Blu-tac is better. Decide when the stickers need to be removed.