Some Wifi Cameras and smart devices etc apps saved wifi password but i want answers of some questions?
(1)These apps saved wifi passwords in apps cloud or in devices like mobile storage?
(2)These wifi passwords linked with user account or device i mean wifi password synced with only user account or when device setup with app?
Every device and service is different, so you would need to ask the developer of each app/device.
For Google, the device would store the wifi information, but would also keep a copy in your Google account as well.