How to update location for Photos and get them updated also in libraries synced on iPhone and iPad ?

How are you syncing with the iPad and iPhone via iCloud?

All of these have been synced also into libraries of mine iPhone and iPad via-iCloud.

• If you are using iCloud Photo Library to keep the devices in sync, and add a new location in the Info panel of the photo, the updated location should sync across all devices.
• But if you sync only with My Photo Stream or iCloud Photo Sharing, the photos you shared will not be updated in the streams. You have to share the adjusted photo again, because these albums are streaming the photos the way they have been when you add the photo the stream. They will not be updated across all devices, when you later edit them on one device.

But... how could I share the adjusted photos again ?

That is tricky in Photos, because the phots will only upload to My Photo Stream on Import in Photos. You could export the edited version in a high quality and reimport it.