How to save game data to iCloud?

>I want the user....so they can play on multiple devices

If you want to access information from multiple devices with all the devices logged into the same Apple ID (i.e. what you wrote above) then you can use the iCloud key-value file.

https://developer.apple.com/library/archive/documentation/General/Conceptual/iCloudDesignGuide/Chapters/DesigningForKey-ValueDataIniCloud.html#//apple_ref/doc/uid/TP40012094-CH7-SW1

If you want users to be able to access the same data from multiple devices logged into different Apple ID's then you will need to use the public database of CloudKit.

https://developer.apple.com/documentation/cloudkit?language=objc

Do u know if there is a plugin or a tutorial step-by-step that shows u excatly how to implent, and do I need to learn Swift because I'am coding in C#.

I am sure there are tutorials. Search for NSUbiquitousKeyValueStore.

here is the Apple document:

https://developer.apple.com/library/archive/documentation/General/Conceptual/iCloudDesignGuide/Chapters/DesigningForKey-ValueDataIniCloud.html#//apple_ref/doc/uid/TP40012094-CH7-SW9

You don't need to learn Swift. It is unclear whether you will need to learn Objective C or whether your C# and the tutorial will work.

I think it is as simple as:

//to store a string
        NSUbiquitousKeyValueStore* store = [NSUbiquitousKeyValueStore defaultStore];
        [store setString:@"My string that I am storing" forKey:@"My String"];
        [store synchronize];

//to recover the string
    NSUbiquitousKeyValueStore* store = [NSUbiquitousKeyValueStore defaultStore];
    NSDictionary *iCloudDictionary=[store dictionaryRepresentation];
    NSString *recoveredString=[iCloudDictionary objectForKey:@"My String"];

Thank you for your reply! My last questions are: if I have a simple "public int number = 5;" in my C# script, where will that "number" be after building to Xcode, can I reference it by name and if so in what class do I have to implement ur code that u send me? And the last thing, how do I handle (or with what code) a situation where there are different versions stored on someones devices and iCloud and let the player chose between them.

I don't do C# but I guess that you need to create an NSNumber object:

[store setNumber:[NSNumber numberWithInt:number] forKey@"My Number"];

and recover it with

number=[[iCloudDictionary objectForKey:@"My Number"] intValue];

Hi did you manage to implement it? Could you please share the Unity script if so?

Hello, Has anyone implemented this ? Any tutorial or help will be much appreciated.