On OpenStreetMap, there’s an emergency=defibrillator object. It can be tagged with information like opening hours (e.g. if it’s inside a location that’s only open certain hours), a description of the location (“at the front desk”), etc.
For example, on the Android/iOS app OsmAnd, you can select ‘Defibrillator’ as a point of interest (POI) Additionally, choosing ‘Healthcare’ POI type will show not just hospitals, clinics, etc., but also AED locations.
Other emergency devices, like emergency phones, are also mappable.
Why YSK: quick access to defibrillators can save lives and significantly improve quality-of-life outcomes. The more complete this data is, the more useful somebody can actually expect it to be in an emergency. Even if the data isn’t queried during the emergency, seeing it on the map could help users know where they are ahead of time.
I don’t use iOS, but have read that there are apps for it too. On Android there is something called StreetComplete that is specifically aimed at beginners.
Probably the easiest thing to do on mobile is to add or update nodes describing POIs. For example if a store or restaurant or post box or trash can is missing on the map, you can add that. You can use OsmAnd or, I think, also CoMaps for that.